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NCERT Solutions Class 9 Maths Chapter 1 - Number Systems

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• Chapter 1 Number Systems

NCERT Solutions for Class 9 Maths Chapter 1 Number System - Free PDF 2024-25

Chapter 1 number system class 9 delves into the principles covered under the topic of the number system. Vedantu offers an expert-curated NCERT answer for CBSE Class 9 Chapter 1. To ace your preparations, get the NCERT solution supplied by our professionals. The freely available number system class 9 PDF offers step-by-step solutions to the NCERT practice problems. The NCERT solutions PDF for chapter 1 maths class 9 contains the answers to all the Class 9 syllabus questions.

Glance of NCERT Solutions for Class 9 Maths Chapter 1 Number System | Vedantu

Class 9 chapter 1 maths dives into the fundamental building block of mathematics: Numbers! It introduces different types of number systems that we use for counting and calculations.

You will learn about various number systems like natural numbers (whole numbers starting from 1), whole numbers (including 0 with natural numbers), integers (whole numbers and their negatives), rational numbers (numbers expressible as a fraction p/q where q ≠ 0), and irrational numbers (numbers that cannot be expressed as a fraction, like the square root of 2).

The chapter explores properties like closure, commutativity, associativity, and distributivity for different operations (addition, subtraction, multiplication, division) on these number systems.

You will revisit how to represent these numbers on the number line, which is a visual aid to understand their relative positions and comparisons.

This article contains chapter notes, important questions, exemplar solutions and exercises links for Chapter 1 - Number System, which you can download as PDFs.

There are six exercises (27 fully solved questions) in class 10th maths chapter 3 Pair of Linear Equations in Two Variables.

Access Exercise Wise NCERT Solutions for Chapter 1 Maths Class 9

Exercises under NCERT Solutions for Class 9 Maths Chapter 1 Number Systems

Exercise 1.1: This exercise covers basic concepts of the number system, such as natural numbers, whole numbers, integers, rational numbers, irrational numbers, etc. The questions in this exercise aim to familiarise students with these concepts and their properties.

Exercise 1.2: This exercise covers the representation of numbers in decimal form. The questions in this exercise require students to convert fractions into decimals, decimals into fractions, and perform basic operations such as addition, subtraction, multiplication, and division on decimals.

Exercise 1.3: This exercise deals with the representation of rational numbers on a number line. The questions in this exercise require students to mark the position of given rational numbers on a number line and identify the rational number represented by a given point on the number line.

Exercise 1.4: This exercise deals with the conversion of recurring decimals into fractions. The questions in this exercise require students to write recurring decimals as fractions and vice versa.

Exercise 1.5: This exercise covers the comparison of rational numbers. The questions in this exercise require students to compare given rational numbers using the concept of inequality, find rational numbers between two given rational numbers, and represent rational numbers on a number line.

NCERT Solutions Class 9 Maths Chapter 1 Number System - Free PDF Download

Exercise (1.1).

1.  Is zero a rational number? Can you write it in the form  $\dfrac{ {p}}{ {q}}$, where $ {p}$ and $ {q}$ are integers and $ {q}\ne  {0}$? Describe it.

Ans: Remember that, according to the definition of rational number,

a rational number is a number that can be expressed in the form of  $\dfrac{p}{q}$, where $p$ and $q$ are integers and  $q\ne \text{0}$.

Now, notice that zero can be represented as $\dfrac{0}{1},\dfrac{0}{2},\dfrac{0}{3},\dfrac{0}{4},\dfrac{0}{5}.....$

Also, it can be expressed as $\dfrac{0}{-1},\dfrac{0}{-2},\dfrac{0}{-3},\dfrac{0}{-4}.....$

Therefore, it is concluded from here that $0$ can be expressed in the form of $\dfrac{p}{q}$, where $p$ and $q$ are integers.

Hence, zero must be a rational number.

2. Find any six rational numbers between $ {3}$ and $ {4}$. 

Ans: It is known that there are infinitely many rational numbers between any two numbers. Since we need to find $6$ rational numbers between $3$ and $4$, so multiply and divide the numbers by $7$ (or by any number greater than $6$)

Then it gives, 

$ 3=3\times \dfrac{7}{7}=\dfrac{21}{7} $ 

$  4=4\times \dfrac{7}{7}=\dfrac{28}{7} $

Hence, $6$ rational numbers found between $3$ and $4$ are $\dfrac{22}{7},\dfrac{23}{7},\dfrac{24}{7},\dfrac{25}{7},\dfrac{26}{7},\dfrac{27}{7}$.

3. Find any five rational numbers between $\dfrac{ {3}}{ {5}}$ and $\dfrac{ {4}}{ {5}}$.

Ans: It is known that there are infinitely many rational numbers between any two numbers.

Since here we need to find five rational numbers between $\dfrac{3}{5}$ and $\dfrac{4}{5}$,  so multiply and divide by $6$ (or by any number greater than $5$).

Then it gives,

$\dfrac{3}{5}=\dfrac{3}{5}\times \dfrac{6}{6}=\dfrac{18}{30}$,

$\dfrac{4}{5}=\dfrac{4}{5}\times \dfrac{6}{6}=\dfrac{24}{30}$.

Hence, $5$ rational numbers found between $\dfrac{3}{5}$ and $\dfrac{4}{5}$ are

$\dfrac{19}{30},\dfrac{20}{30},\dfrac{21}{30},\dfrac{22}{30},\dfrac{23}{30}$.

4. State whether the following statements are true or false. Give reasons for your answers. 

(i) Every natural number is a whole number. 

Ans: Write the whole numbers and natural numbers in a separate manner.

It is known that the whole number series is $0,1,2,3,4,5.....$. and the natural number series is $1,2,3,4,5...$.

Therefore, it is concluded that all the natural numbers lie in the whole number series as represented in the diagram given below.

Thus, it is concluded that every natural number is a whole number.

Hence, the given statement is true.

(ii) Every integer is a whole number.

Ans: Write the integers and whole numbers in a separate manner.

It is known that integers are those rational numbers that can be expressed in the form of $\dfrac{p}{q}$, where $q=1$.

Now, the series of integers is like $0,\,\pm 1,\,\pm 2,\,\pm 3,\,\pm 4,\,...$.

But the whole numbers are $0,1,2,3,4,...$.

Therefore, it is seen that all the whole numbers lie within the integer numbers, but the negative integers are not included in the whole number series.

Thus, it can be concluded from here that every integer is not a whole number.

Hence, the given statement is false.

(iii) Every rational number is a whole number.

Ans: Write the rational numbers and whole numbers in a separate manner.

It is known that rational numbers are the numbers that can be expressed in the form  $\dfrac{p}{q}$, where $q\ne 0$ and the whole numbers are represented as $0,\,1,\,2,\,3,\,4,\,5,...$

Now, notice that every whole number can be expressed in the form of $\dfrac{p}{q}$

as  \[\dfrac{0}{1},\text{ }\dfrac{1}{1},\text{ }\dfrac{2}{1},\text{ }\dfrac{3}{1},\text{ }\dfrac{4}{1},\text{ }\dfrac{5}{1}\],…

Thus, every whole number is a rational number, but all the rational numbers are not whole numbers. For example,

$\dfrac{1}{2},\dfrac{1}{3},\dfrac{1}{4},\dfrac{1}{5},...$ are not whole numbers.

Therefore, it is concluded from here that every rational number is not a whole number.

Exercise (1.2)

1. State whether the following statements are true or false. Justify your answers.

(i) Every irrational number is a real number. 

Ans: Write the irrational numbers and the real numbers in a separate manner.

The irrational numbers are the numbers that cannot be represented in the form $\dfrac{p}{q},$ where $p$ and $q$ are integers and $q\ne 0.$

For example, $\sqrt{2},3\pi ,\text{ }.011011011...$ are all irrational numbers.

The real number is the collection of both rational numbers and irrational numbers.

For example, $0,\,\pm \dfrac{1}{2},\,\pm \sqrt{2}\,,\pm \pi ,...$ are all real numbers.

Thus, it is concluded that every irrational number is a real number.

(ii) Every point on the number line is of the form $\sqrt{m}$, where m is a natural number. 

Ans: Consider points on a number line to represent negative as well as positive numbers.

Observe that, positive numbers on the number line can be expressed as $\sqrt{1,}\sqrt{1.1,}\sqrt{1.2},\sqrt{1.3},\,...$, but any negative number on the number line cannot be expressed as $\sqrt{-1},\sqrt{-1.1},\sqrt{-1.2},\sqrt{-1.3},...$, because these are not real numbers.

Therefore, it is concluded from here that every number point on the number line is not of the form $\sqrt{m}$, where $m$ is a natural number.

(iii) Every real number is an irrational number. 

Real numbers are the collection of rational numbers (Ex: $\dfrac{1}{2},\dfrac{2}{3},\dfrac{3}{5},\dfrac{5}{7},$……) and the irrational numbers (Ex: $\sqrt{2},3\pi ,\text{ }.011011011...$).

Therefore, it can be concluded that every irrational number is a real number, but

every real number cannot be an irrational number.

2. Are the square roots of all positive integer numbers irrational? If not, provide an example of the square root of a number that is not an irrational number.

Ans: Square root of every positive integer does not give an integer.

For example: $\sqrt{2},\sqrt{3,}\sqrt{5},\sqrt{6},...$ are not integers, and hence these are irrational numbers. But $\sqrt{4}$ gives $\pm 2$ , these are integers and so, $\sqrt{4}$ is not an irrational number.

Therefore, it is concluded that the square root of every positive integer is not an irrational number.

3. Represent $\sqrt{5}$ on the number line.

Ans: Follow the procedures to get $\sqrt{5}$ on the number line.

Firstly, Draw a line segment $AB$ of $2$ unit on the number line.

Secondly, draw a perpendicular line segment $BC$ at $B$ of $1$ units.

Thirdly, join the points $C$ and $A$, to form a line segment $AC$. 

Fourthly, apply the Pythagoras Theorem as 

$ A{{C}^{2}}=A{{B}^{2}}+B{{C}^{2}} $

$  A{{C}^{2}}={{2}^{2}}+{{1}^{2}} $

$ A{{C}^{2}}=4+1=5 $

$ AC=\sqrt{5} $

Finally, draw the arc $ACD$, to find the number $\sqrt{5}$ on the number line as given in the diagram below.

Exercise (1.3)

1. Write the following in decimal form and say what kind of decimal expansion each has:

(i) $\mathbf{\dfrac{ {36}}{ {100}}}$

Ans: Divide $36$ by $100$. 

$\,\,\,\,\,\,\,\,\,\, {0.36}$

$100 {\overline{)\;36\quad}}$

$\underline{\,\,\,\,\,\,\,\,\,-0\quad}$

$\,\,\,\,\,\,\,\,\,\,\,\,\,\,360$

$\underline{\,\,\,\,\,\,\,\,\,\,-300\quad}$

$\;\;\,\,\,\,\,\,\,\,\,\,\,\,\,\,600$

$\underline{\,\,\,\,\,\,\,\,\,\,\,\,\,-600}$

$\underline{\,\,\,\,\,\,\,\,\,\,\,\,\quad 0 \,\,\,\,\,}$

So, $\dfrac{36}{100}=0.36$ and it is a terminating decimal number.

(ii) $\mathbf{\dfrac{ {1}}{ {11}}}$

Ans: Divide $1$ by $11$.

${\,\,\,\,\,\,\,\,0.0909..}$

$11 \, {\overline{)\;1\quad}}$

$\underline{\,\,\,\,\,\,\,-0\quad}$

$\,\,\,\,\,\,\,\,\,\,10$

$\underline{\,\;\;\,\,-0\quad}$

$\;\;\,\,\,\,100$

$\underline{\,\,\,\,\;-99}$

$\,\,\,\,\,\, \quad 10$

$\quad\underline{\;\;-0\quad}$

$\;\;\,\,\,\,\,\,\,\,100$

$\underline{\,\,\,\,\,\,\,\,\;-99}$

$\quad\,\,\,\,\,\,\,1\quad$

It is noticed that while dividing $1$ by $11$, in the quotient $09$ is repeated.

So, $\dfrac{1}{11}=0.0909.....$ or 

$\dfrac{1}{11}=0.\overline{09}$ 

and it is a non-terminating and recurring decimal number.

(iii)  $ \mathbf{{4}\dfrac{ {1}}{ {8}}}$

Ans: $4\dfrac{1}{8}=4+\dfrac{1}{8}=\dfrac{32+1}{8}=\dfrac{33}{8}$

Divide $33$ by $8$.

$\,\,\,\,\,{4.125}$

$8 {\overline{)\;33\quad}}$

$\underline{\,\,\,\,-32\quad}$

$\,\,\,\,\,\,\,\,\,\,\,\,10$

$\underline{\;\;\,\,\,\,-8\quad}$

$\;\;\,\,\,\,\,\,\,\,\,\,\,20$

$\underline{\,\,\,\,\,\,\,\,\,-16}$

$\;\quad\quad\,\,\,\,40$

$\quad\underline{\quad\,\,-40\quad}$

$\quad\underline{\quad\,\, \,\,\,\,0\quad}$

Notice that, after dividing $33$ by $8$, the remainder is found as $0$.

So, $4\dfrac{1}{8}=4.125$ and it is a terminating decimal number.

(iv)  $\mathbf{\dfrac{ {3}}{ {13}}}$

Ans: Divide $3$ by $13$.

$\quad \,\,{0.230769}$

$13 {\overline{)\;3\quad}}$

$\underline{\quad-0\quad}$

$\quad\quad 30$

$\underline{\;\,\quad-26\quad}$

$\;\quad\quad\,\,\,40$

$\underline{\quad\quad\,\,-39\quad}$

$\;\quad\quad\quad\;10$

$\quad\underline{\quad\quad -0\quad}$

$\quad{\quad\quad \quad 100}$

$\quad\quad\underline{\quad \,\, -91\quad}$

$\quad\quad \quad \,\,\,\quad90$

$\quad\quad\underline{\quad\,\,\,\,\,-78\quad}$

$\quad\quad\quad\quad \quad 120$

$\quad \quad\underline{\quad\quad\,\,-117\quad}$

$\quad\quad\underline{\quad \quad\quad\,\, 3\quad}$

It is observed that while dividing $3$ by $13$, the remainder is found as $3$ and that is repeated after each $6$ continuous divisions.

So, $\dfrac{3}{13}=0.230769.......$ or

$\dfrac{3}{13}=0.\overline{230769}$ 

(v)   $\mathbf{\dfrac{ {2}}{ {11}}}$

Ans: Divide $2$ by $11$.

$\quad \,\,{0.1818}$

$11 {\overline{)\;2\quad}}$

$\quad\quad20$

$\underline{\quad\;-11\quad}$

$\quad\quad \;\,90$

$\underline{\quad\,\,\,\, -88\;}$

$\;\quad\quad\;20$

$\quad\underline{\quad-11\quad}$

$\quad{\quad\quad  90}$

$\quad\underline{\,\,\quad -88}$

$\quad\quad\quad\,\,2\quad$

It can be noticed that while dividing $2$ by $11$, the remainder is obtained as $2$ and then $9$, and these two numbers are repeated infinitely as remainders.

So, $\dfrac{2}{11}=0.1818.....$ or 

$\dfrac{2}{11}=0.\overline{18}$ 

(vi) $\mathbf{\dfrac{ {329}}{ {400}}}$

Ans: Divide $329$ by $400$.

$\quad \quad{0.8225}$

$400 {\overline{)\;329\quad}}$

$\underline{\quad\,\,-0\quad}$

$\quad\quad3290$

$\underline{\quad\;-3200\quad}$

$\quad\quad\quad\;900$

$\underline{\quad\quad\quad-800\;}$

$\quad\quad\quad\quad\;1000$

$\quad\underline{\quad\quad\quad-800\quad}$

$\quad{\quad\quad\quad\quad\,\,2000}$

$\quad\underline{\quad\quad\quad\quad-2000\quad}$

$\quad\underline{\quad\quad\quad\quad\,\,\,\,\,\, 0 \quad}$

It can be seen that while dividing $329$ by $400$, the remainder is obtained as $0$.

So, $\dfrac{329}{400}=0.8225$ and is a terminating decimal number.

2. You know that $\dfrac{ {1}}{ {7}} {=0} {.142857}...$. Can you predict what the decimal expansions of $\dfrac{ {2}}{ {7}} {,}\dfrac{ {3}}{ {7}} {,}\dfrac{ {4}}{ {7}} {,}\dfrac{ {5}}{ {7}} {,}\dfrac{ {6}}{ {7}}$  are, without actually doing the long division? If so, how?

$\text{[}$Hint: Study the remainders while finding the value of $\dfrac{ {1}}{ {7}}$ carefully.$\text{]}$

Ans: Note that,  $\dfrac{2}{7},\dfrac{3}{7},\dfrac{4}{7},\dfrac{5}{7}$ and $\dfrac{6}{7}$ can be rewritten as $2\times \dfrac{1}{7},\text{ 3}\times \dfrac{1}{7},\text{ 4}\times \dfrac{1}{7},\text{ 5}\times \dfrac{1}{7},$ and $6\times \dfrac{1}{7}$

Substituting the value of $\dfrac{1}{7}=0.142857$ , gives 

$2 \times \dfrac{1}{7} = 2\times 0.142857...=0.285714...$

$ 3\times \dfrac{1}{7} = 3\times .428571…= .428571...$

\[4\times \dfrac{1}{7}=4\times 0.142857...\]\[\text{=}\,\text{0}\text{.571428}...\]

$5\times \dfrac{1}{7}=5\times 0.71425...$  \[\text{=}\,\text{0}\text{.714285}...\]

$6\times \dfrac{1}{7}=6\times 0.142857...$\[\text{=}\,\text{0}\text{.857142}...\]

So, the values of $\dfrac{2}{7},\text{ }\dfrac{3}{7},\text{ }\dfrac{4}{7},\text{ }\dfrac{5}{7}$ and $\dfrac{6}{7}$ obtained without performing long division are

\[\dfrac{2}{7}=0.\overline{285714}\]

$\dfrac{3}{7}=0.\overline{428571}$

$\dfrac{4}{7}=0.\overline{571428}$

\[\dfrac{5}{7}=0.\overline{714285}\]

$\dfrac{6}{7}=0.\overline{857142}$

3. Express the following in the form \[\dfrac{ {p}}{ {q}}\], where $ {p}$ and $ {q}$ are integers and $ {q}\ne  {0}$.

(i) $\mathbf{ {0} {.}\overline{ {6}}}$

Ans: Let $x=0.\overline{6}$  

 $\Rightarrow x=0.6666$                                                   ….… (1)

 Multiplying both sides of the equation (1) by $10$, gives

$10x=0.6666\times 10$

$10x=6.6666$…..                 …… (2)

Subtracting the equation $\left( 1 \right)$ from $\left( 2 \right)$, gives

$ 10x=6.6666..... $

$ \underline{-x=0.6666.....} $

$  9x=6 $ 

$  9x=6 $

$  x=\dfrac{6}{9}=\dfrac{2}{3} $ 

So, the decimal number becomes

$0.\overline{6}=\dfrac{2}{3}$  and it is in the required  $\dfrac{p}{q}$ form.

(ii) $\mathbf{ {0} {.}\overline{ {47}}}$

Ans: Let  $x=0.\overline{47}$

$\text{   }\Rightarrow x=0.47777.....$                                             ……(a)

Multiplying both sides of the equation (a) by $10$, gives

$10x=4.7777.....$         ……(b)

Subtracting the equation $\left( a \right)$ from $\left( b \right)$, gives

$ 10x=4.7777..... $

$  \underline{-x=0.4777.....} $

$  9x=4.3 $

$x=\dfrac{4.3}{9}\times \dfrac{10}{10} $ 

$ \Rightarrow x=\dfrac{43}{90} $

So, the decimal number becomes 

$0.\overline{47}=\dfrac{43}{90}$  and it is in the required $\dfrac{p}{q}$ form.

(iii) $ \mathbf{{0} {.}\overline{ {001}}}$

Ans: Let $x=0.\overline{001} $           …… (1)

Since the number of recurring decimal number is $3$, so multiplying both sides of the equation (1) by $1000$, gives

$1000\times x=1000\times 0.001001.....$ …… (2)

Subtracting the equation (1) from (2) gives

$ 1000x=1.001001..... $

$  \underline{\text{    }-x=0.001001.....} $

$  999x=1 $

$\Rightarrow x=\dfrac{1}{999}$

Hence, the decimal number becomes 

$0.\overline{001}=\dfrac{1}{999}$ and it is in the $\dfrac{p}{q}$ form.

4. Express $ {0} {.99999}.....$ in the form of $\dfrac{ {p}}{ {q}}$ . Are you surprised by your answer? With your teacher and classmates, discuss why the answer makes sense.

Let $x=0.99999.....$                                                             ....... (a)

Multiplying by $10$ both sides of the equation (a), gives

$10x=9.9999.....$                                                             …… (b)

Now, subtracting the equation (a) from (b), gives

$ 10x=9.99999..... $

$  \underline{\,-x=0.99999.....} $

$  9x=9 $ 

$\Rightarrow x=\dfrac{9}{9}$

$\Rightarrow x=1$.

$0.99999...=\dfrac{1}{1}$ which is in the $\dfrac{p}{q}$ form.

Yes, for a moment we are amazed by our answer, but when we observe that $0.9999.........$ is extending infinitely, then the answer makes sense.

Therefore, there is no difference between $1$ and $0.9999.........$ and hence these two numbers are equal.

5. What can the maximum number of digits be in the repeating block of digits in the decimal expansion of $\dfrac{ {1}}{ {17}}$ ? Perform the division to check your answer.

Ans: Here the number of digits in the recurring block of $\dfrac{1}{17}$ is to be determined. So, let us calculate the long division to obtain the recurring block of $\dfrac{1}{17}$. Dividing $1$ by $17$ gives

$\quad\quad {0.0588235294117646}$

$17{\overline{)\quad1\quad\quad\quad\quad\quad\quad\quad\quad}}$

$\underline{\quad\,\,\,\,-0\quad}\qquad\qquad\qquad$

$\quad \quad \,\,\,10\qquad\qquad\quad\quad$

$\underline{\quad \quad -0\quad}\qquad\qquad\quad$

$\quad \quad \,\,\,\,\,\;100\qquad\qquad\qquad$

$\underline{\quad \quad \,\,-85\;}\qquad\qquad\quad$

$\quad\qquad\,\,\;150\qquad\qquad\quad$

$\quad\underline{\qquad-136\;}\qquad\qquad\quad$

$\quad{\quad\quad\quad 140}\qquad\qquad\;\;$

$\quad\underline{\qquad-136\quad}\qquad\quad$

${\quad \qquad \,\,\quad 40 \quad}\quad$

$\underline{\qquad \,\,\,\quad -34\;\;}\quad$

$\;\qquad \qquad\,\,60$

$\underline{\qquad \qquad-51}$

$\quad\quad \qquad \quad 90$

$\quad\;\;\underline{\quad \qquad-85}$

$\qquad\quad\;\quad\,\,\,\, 50$

$\quad\quad\;\;\underline{\,\,\quad\,\, -34}$

$\quad\quad\qquad \quad 160$

$\qquad\quad\;\underline{\quad-153}$

$\qquad\qquad\quad\;70$

$\qquad\quad\quad\;\;\underline{-68}$

$\quad\,\,\qquad\qquad 20$

$\qquad\qquad\quad\underline{-17}$

$\qquad\qquad\quad\quad\; 130$

$\qquad\qquad\quad\;\;\underline{-119}$

$\qquad\qquad\qquad\quad 110$

$\qquad\qquad\qquad\;\;\underline{-102}$

$\qquad\qquad\qquad\quad\quad\quad 80$

$\qquad\qquad\qquad\qquad\;\underline{-68}$

$\qquad\qquad\qquad\quad\quad\quad\; 120$

$\qquad\qquad\qquad\qquad\;\;\underline{-119}$

$\qquad\qquad\qquad\quad\quad\quad\; 1$

Thus, it is noticed that while dividing $1$ by $17$, we found $16$ number of digits in the

repeating block of decimal expansion that will continue to be $1$ after going through $16$ continuous divisions.

Hence, it is concluded that $\dfrac{1}{17}=0.0588235294117647.....$ or 

 $\dfrac{1}{17}=0.\overline{0588235294117647}$ and it is a recurring and non-terminating decimal number.

6. Look at several examples of rational numbers in the form $\dfrac{ {p}}{ {q}}\left(  {q}\ne  {0} \right)$, where $ {p}$ and $ {q}$ are integers with no common factors other than $ {1}$ and having terminating decimal representations (expansions). Can you guess what property $ {q}$ must satisfy?

Ans: Let us consider the examples of such rational numbers $\dfrac{5}{2},\dfrac{5}{4},\dfrac{2}{5},\dfrac{2}{10},\dfrac{5}{16}$ of the form $\dfrac{p}{q}$ which have terminating decimal representations.

$ \dfrac{5}{2}=2.5 $

$ \dfrac{5}{4}=1.25 $ 

$ \dfrac{2}{5}=0.4 $

$ \dfrac{2}{10}=0.2 $

$ \dfrac{5}{16}=0.3125 $

In each of the above examples, it can be noticed that the denominators of the rational numbers have powers of $2,5$ or both.

So, $q$ must satisfy the form either ${{2}^{m}}$, or ${{5}^{n}}$, or  both ${{2}^{m}}\times {{5}^{n}}$ (where $m=0,1,2,3.....$ and $n=0,1,2,3.....$) in the form of $\dfrac{p}{q}$.

7. Write three numbers whose decimal expansions are non-terminating non-recurring.

Ans: All the irrational numbers are non-terminating and non-recurring, because irrational numbers do not have any representations of the form of $\dfrac{p}{q}$ $\left( q\ne 0 \right)$, where $p$ and $q$are integers. For example: 

$\sqrt{2}=1.41421.....$,

$\sqrt{3}=1.73205...$

$\sqrt{7}=2.645751....$

are the numbers whose decimal representations are non-terminating and non-recurring.

8. Find any three irrational numbers between the rational numbers $\dfrac{ {5}}{ {7}}$ and $\dfrac{ {9}}{ {11}}$.

Ans: Converting  $\dfrac{5}{7}$and $\dfrac{9}{11}$ into the decimal form gives

$\dfrac{5}{7}=0.714285.....$ and 

$\dfrac{9}{11}=0.818181.....$

Therefore, $3$ irrational numbers that are contained between $0.714285......$ and $0.818181.....$

$ 0.73073007300073...... $ 

$  0.74074007400074...... $ 

$ 0.76076007600076...... $

Hence, three irrational numbers between the rational numbers $\dfrac{5}{7}$ and $\dfrac{9}{11}$ are

9. Classify the following numbers as rational or irrational:

(i) $\mathbf{\sqrt{ {23}}}$

Ans: The following diagram reminds us of the distinctions among the types of rational and irrational numbers.

After evaluating the square root gives

$\sqrt{23}=4.795831.....$ , which is an irrational number.

(ii) $\mathbf{\sqrt{ {225}}}$

Ans: After evaluating the square root gives

$\sqrt{225}=15$, which is a rational number.

That is, $\sqrt{225}$ is a rational number.

(iii) $ \mathbf{{0} {.3796}}$

Ans: The given number is $0.3796$. It is terminating decimal. 

So, $0.3796$ is a rational number.

(iv) $ \mathbf{{7} {.478478}}$

Ans: The given number is \[7.478478\ldots .\] 

It is a non-terminating and recurring decimal that can be written in the $\dfrac{p}{q}$ form.

Let      $x=7.478478\ldots .$                                   ……(a)

Multiplying the equation (a) both sides by $100$ gives

$\Rightarrow 1000x=7478.478478.....$                                               ……(b)

Subtracting the equation (a) from (b), gives

$ 1000x=7478.478478.... $

$  \underline{\text{    }-x=\text{     }7.478478\ldots .} $

$ 999x=7471 $

$  \text{      }x=\dfrac{7471}{999} $

Therefore, $7.478478.....=\dfrac{7471}{999}$, which is in the form of $\dfrac{p}{q}$

So, $7.478478...$ is a rational number.

(v) $ \mathbf{{1} {.101001000100001}.....}$

Ans: The given number is \[1.101001000100001....\]

It can be clearly seen that the number \[1.101001000100001....\] is a non-terminating and non-recurring decimal and it is known that non-terminating non-recurring decimals cannot be written in the form of $\dfrac{p}{q}$.

Hence, the number \[1.101001000100001....\] is an irrational number.

Exercise (1.4)

1.  Classify the following numbers as rational or irrational:

(i) $ \mathbf{{2-}\sqrt{ {5}}}$

Ans: The given number is $2-\sqrt{5}$.

Here, $\sqrt{5}=2.236.....$ and it is a non-repeating and non-terminating irrational number.

Therefore, substituting the value of $\sqrt{5}$ gives

$2-\sqrt{5}=2-2.236.....$

$=-0.236.....$, which is an irrational number.

So, $2-\sqrt{5}$ is an irrational number.

(ii) $\mathbf{\left(  {3+}\sqrt{ {23}} \right) {-}\left( \sqrt{ {23}} \right)}$

Ans: The given number is $\left( 3+\sqrt{23} \right)-\left( \sqrt{23} \right)$.

The number can be written as

$\left( 3+\sqrt{23} \right)-\sqrt{23}=3+\sqrt{23}-\sqrt{23} $ 

$  =3 $

$=\dfrac{3}{1}$, which is in the $\dfrac{p}{q}$ form and so, it is a rational number.

Hence, the number $\left( 3+\sqrt{23} \right)-\sqrt{23}$ is a rational number.

(iii) $\mathbf{\dfrac{ {2}\sqrt{ {7}}}{ {7}\sqrt{ {7}}}}$

Ans: The given number is $\dfrac{2\sqrt{7}}{7\sqrt{7}}$.

$\dfrac{2\sqrt{7}}{7\sqrt{7}}=\dfrac{2}{7}$, which is in the $\dfrac{p}{q}$  form and so, it is a rational number.

Hence, the number  $\dfrac{2\sqrt{7}}{7\sqrt{7}}$ is a rational number.

(iv) $\mathbf{\dfrac{ {1}}{\sqrt{ {2}}}}$

Ans: The given number is $\dfrac{1}{\sqrt{2}}$.

It is known that, $\sqrt{2}=1.414.....$ and it is a non-repeating and non-terminating irrational number.

Hence, the number $\dfrac{1}{\sqrt{2}}$ is an irrational number.

(v) $ \mathbf{{2\pi }}$

Ans: The given number is $2\pi $.

It is known that, $\pi =3.1415$ and it is an irrational number.

Now remember that, Rational $\times $ Irrational = Irrational.

Hence, $2\pi $ is also an irrational number.

2. Simplify each of the of the following expressions:

(i) $\mathbf{\left(  {3+}\sqrt{ {3}} \right)\left(  {2+}\sqrt{ {2}} \right)}$

Ans: The given number is $\left( 3+\sqrt{3} \right)\left( 2+\sqrt{2} \right)$.

By calculating the multiplication, it can be written as

$\left( 3+\sqrt{3} \right)\left( 2+\sqrt{2} \right)=3\left( 2+\sqrt{2} \right)+\sqrt{3}\left( 2+\sqrt{2} \right)$.

\[= 6 + 4 \sqrt{2} + 2 \sqrt{3}+ \sqrt{6}\]

(ii) $\mathbf{\left(  {3+}\sqrt{ {3}} \right)\left(  {3-}\sqrt{ {3}} \right)}$

Ans: The given number is $\left( 3+\sqrt{3} \right)\left( 3-\sqrt{3} \right)$.

By applying the formula $\left( a+b \right)\left( a-b \right)={{a}^{2}}-{{b}^{2}}$, the number can be written as

$\left( 3+\sqrt{3} \right)\left( 3-\sqrt{3} \right)={{3}^{2}}-{{\left( \sqrt{3} \right)}^{2}}=9-3=6$.

(iii)  $\mathbf{{{\left( \sqrt{ {5}} {+}\sqrt{ {2}} \right)}^{ {2}}}}$

Ans: The given number is ${{\left( \sqrt{5}+\sqrt{2} \right)}^{2}}$.

Applying the formula ${{\left( a+b \right)}^{2}}={{a}^{2+}}2ab+{{b}^{2}}$, the number can be written as

${{\left( \sqrt{5}+\sqrt{2} \right)}^{2}}={{\left( \sqrt{5} \right)}^{2}}+2\sqrt{5}\sqrt{2}+{{\left( \sqrt{2} \right)}^{2}}$

 $=5+2\sqrt{10}+2$

 $=7+2\sqrt{10}$.

(iv)  $\mathbf{\left( \sqrt{ {5}}-\sqrt{ {2}} \right)\left( \sqrt{ {5}} {+}\sqrt{ {2}} \right)}$

Ans: The given number is $\left( \sqrt{5}-\sqrt{2} \right)\left( \sqrt{5}+\sqrt{2} \right)$.

Applying the formula $\left( a+b \right)\left( a-b \right)={{a}^{2}}-{{b}^{2}}$, the number can be expressed as

$\left( \sqrt{5}-\sqrt{2} \right)\left( \sqrt{5}+\sqrt{2} \right)={{\left( \sqrt{5} \right)}^{2}}-{{\left( \sqrt{2} \right)}^{2}}$

$ =3. $ 

3. Recall that, $ {\pi }$ is defined as the ratio of the circumference (say $ {c}$) of a circle to its diameter (say $ {d}$). That is, $ {\pi =}\dfrac{ {c}}{ {d}}$ .This seems to contradict the fact that $ {\pi }$ is irrational. How will you resolve this contradiction?

Ans: It is known that, $\pi =\dfrac{22}{7}$, which is a rational number. But, note that this value of $\pi $ is an approximation.

On dividing $22$ by $7$, the quotient $3.14...$ is a non-recurring and non-terminating number. Therefore, it is an irrational number.

In order of increasing accuracy, approximate fractions are

$\dfrac{22}{7}$, $\dfrac{333}{106}$, $\dfrac{355}{113}$, $\dfrac{52163}{16604}$, $\dfrac{103993}{33102}$, and \[\dfrac{245850922}{78256779}\].

Each of the above quotients has the value $3.14...$, which is a non-recurring and non-terminating number.

Thus, $\pi $ is irrational.

So, either circumference $\left( c \right)$ or diameter $\left( d \right)$ or both should be irrational numbers.

Hence, it is concluded that there is no contradiction regarding the value of $\pi $ and it is made out that the value of $\pi $ is irrational.

4. Represent $\sqrt{ {9} {.3}}$ on the number line.

Ans: Follow the procedure given below to represent the number $\sqrt{9.3}$.

First, mark the distance $9.3$ units from a fixed-point $A$ on the number line to get a point $B$. Then $AB=9.3$ units.

Secondly, from the point $B$ mark a distance of $1$ unit and denote the ending point as $C$.

Thirdly, locate the midpoint of $AC$ and denote it as $O$.

Fourthly, draw a semi-circle to the centre $O$ with the radius $OC=5.15$ units. Then 

$ AC=AB+BC $ 

$  =9.3+1 $ 

$  =10.3 $

So, $OC=\dfrac{AC}{2}=\dfrac{10.3}{2}=5.15$.

Finally, draw a perpendicular line at $B$ and draw an arc to the centre $B$ and then let it meet at the semicircle $AC$ at $D$ as given in the diagram below.

5. Rationalize the denominators of the following:

(i) $\mathbf{\dfrac{ {1}}{\sqrt{ {7}}}}$

Ans: The given number is $\dfrac{1}{\sqrt{7}}$.

Multiplying and dividing by $\sqrt{7}$ to the number gives

$\dfrac{1}{\sqrt{7}}\times \dfrac{\sqrt{7}}{\sqrt{7}}=\dfrac{\sqrt{7}}{7}$.

(ii) $\mathbf{\dfrac{ {1}}{\sqrt{ {7}} {-}\sqrt{ {6}}}}$

Ans: The given number is $\dfrac{1}{\sqrt{7}-\sqrt{6}}$.

Multiplying and dividing by $\sqrt{7}+\sqrt{6}$ to the number gives

$\dfrac{1}{\sqrt{7}-\sqrt{6}}\times \dfrac{\sqrt{7}+\sqrt{6}}{\sqrt{7}+\sqrt{6}}=\dfrac{\sqrt{7}+\sqrt{6}}{\left( \sqrt{7}-\sqrt{6} \right)\left( \sqrt{7}+\sqrt{6} \right)}$

Now, applying the formula $\left( a-b \right)\left( a+b \right)={{a}^{2}}-{{b}^{2}}$ to the denominator gives

$ \dfrac{1}{\sqrt{7}-\sqrt{6}}=\dfrac{\sqrt{7}+\sqrt{6}}{{{\left( \sqrt{7} \right)}^{2}}-{{\left( \sqrt{6} \right)}^{2}}} $ 

$ =\dfrac{\sqrt{7}+\sqrt{6}}{7-6} $ 

$  =\dfrac{\sqrt{7}+\sqrt{6}}{1}. $

(iii) $\mathbf{\dfrac{ {1}}{\sqrt{ {5}} {+}\sqrt{ {2}}}}$

Ans: The given number is $\dfrac{1}{\sqrt{5}+\sqrt{2}}$.

Multiplying and dividing by $\sqrt{5}-\sqrt{2}$ to the number gives

$\dfrac{1}{\sqrt{5}+\sqrt{2}}\times \dfrac{\sqrt{5}-\sqrt{2}}{\sqrt{5}-\sqrt{2}}=\dfrac{\sqrt{5}-\sqrt{2}}{\left( \sqrt{5}+\sqrt{2} \right)\left( \sqrt{5}-\sqrt{2} \right)}$

Now, applying the formula $\left( a+b \right)\left( a-b \right)={{a}^{2}}-{{b}^{2}}$  to the denominator gives

$ \dfrac{1}{\sqrt{5}+\sqrt{2}}=\dfrac{\sqrt{5}-\sqrt{2}}{{{\left( \sqrt{5} \right)}^{2}}-{{\left( \sqrt{2} \right)}^{2}}} $ 

$ =\dfrac{\sqrt{5}-\sqrt{2}}{5-2} $

$ =\dfrac{\sqrt{5}-\sqrt{2}}{3}. $ 

(iv) $\mathbf{\dfrac{ {1}}{\sqrt{ {7}} {-2}}}$

Ans: The given number is $\dfrac{1}{\sqrt{7}-2}$.

Multiplying and dividing by $\sqrt{7}+2$ to the number gives

$\dfrac{1}{\sqrt{7}-2}=\dfrac{\sqrt{7}+2}{\left( \sqrt{7}-2 \right)\left( \sqrt{7}+2 \right)}\\$.

Now, applying the formula $\left( a+b \right)\left( a-b \right)={{a}^{2}}-{{b}^{2}}$ to the denominator gives

$ \dfrac{1}{\sqrt{7}-2}=\dfrac{\sqrt{7}+2}{{{\left( \sqrt{7} \right)}^{2}}-{{\left( 2 \right)}^{2}}} $

$ =\dfrac{\sqrt{7}+2}{7-4} $ 

$  =\dfrac{\sqrt{7}+2}{3}. $

Exercise (1.5)

1. Compute the value of each of the following expressions:

(i) $\mathbf{ {6}{{ {4}}^{\dfrac{ {1}}{ {2}}}}}$

Ans: The given number is \[{{64}^{\dfrac{1}{2}}}\].

By the laws of indices,

${{a}^{\dfrac{m}{n}}}=\sqrt[n]{{{a}^{m}}}$, where$a>0$.

$ {{64}^{\dfrac{1}{2}}}=\sqrt[2]{64} $

$  =\sqrt[2]{8\times \text{8}} $

$  =8. $

Hence, the value of ${{64}^{\dfrac{1}{2}}}$ is $8$.

(ii) $ \mathbf{{3}{{ {2}}^{\dfrac{ {1}}{ {5}}}}}$

Ans: The given number is ${{32}^{\dfrac{1}{5}}}$.

${{a}^{\dfrac{m}{n}}}=\sqrt[m]{{{a}^{m}}}$, where $a>0$

$ {{32}^{\dfrac{1}{5}}}=\sqrt[5]{32}$

$ =\sqrt[5]{2\times 2\times 2\times 2\times 2} $ 

$ =\sqrt[5]{{{2}^{5}}} $

Alternative Method:

By the law of indices ${{\left( {{a}^{m}} \right)}^{n}}={{a}^{mn}}$, then it gives

$ {{32}^{\dfrac{1}{5}}}={{(2\times 2\times 2\times 2\times 2)}^{\dfrac{1}{5}}}$ 

$ ={{\left( {{2}^{5}} \right)}^{\dfrac{1}{5}}} $

$ ={{2}^{\dfrac{5}{5}}} $

Hence, the value of the expression ${{32}^{\dfrac{1}{5}}}$ is $2$.

(iii) $\mathbf{{12}{{ {5}}^{\dfrac{ {1}}{ {5}}}}}$

Ans: The given number is ${{125}^{\dfrac{1}{3}}}$.

By the laws of indices

${{a}^{\dfrac{m}{n}}}=\sqrt[n]{{{a}^{m}}}$ where$a>0$.

$ {{125}^{\dfrac{1}{3}}}=\sqrt[3]{125} $

$  =\sqrt[3]{5\times 5\times 5} $

$  =5. $

Hence, the value of the expression ${{125}^{\dfrac{1}{3}}}$ is $5$.

2. Compute the value of each of the following expressions:

(i) $\mathbf{{{ {9}}^{\dfrac{ {3}}{ {2}}}}}$

Ans: The given number is ${{9}^{\dfrac{3}{2}}}$.

 ${{a}^{\dfrac{m}{n}}}=\sqrt[n]{{{a}^{m}}}$ where $a>0$.

$ {{9}^{\dfrac{3}{2}}}=\sqrt[2]{{{\left( 9 \right)}^{3}}} $

$  =\sqrt[2]{9\times 9\times 9} $

$ =\sqrt[2]{3\times 3\times 3\times 3\times 3\times 3} $

$=3\times 3\times 3 $

By the laws of indices, ${{\left( {{a}^{m}} \right)}^{n}}={{a}^{mn}}$, then it gives

$ {{9}^{\dfrac{3}{2}}}={{\left( 3\times 3 \right)}^{\dfrac{3}{2}}}$

$  ={{\left( {{3}^{2}} \right)}^{\dfrac{3}{2}}} $

$  ={{3}^{2\times \dfrac{3}{2}}} $

$ ={{3}^{3}} $

${{9}^{\dfrac{3}{2}}}=27.$

Hence, the value of the expression ${{9}^{\dfrac{3}{2}}}$ is $27$.

(ii) $\mathbf{{3}{{ {2}}^{\dfrac{ {2}}{ {5}}}}}$

Ans: We know that ${{a}^{\dfrac{m}{n}}}=\sqrt[n]{{{a}^{m}}}$ where $a>0$.

We conclude that ${{32}^{\dfrac{2}{5}}}$ can also be written as

$ \sqrt[5]{{{\left( 32 \right)}^{2}}}=\sqrt[5]{\left( 2\times 2\times 2\times 2\times 2 \right)\times \left( 2\times 2\times 2\times 2\times 2 \right)} $ 

$  =2\times 2 $

$ =4 $ 

Therefore, the value of ${{32}^{\dfrac{2}{5}}}$ is $4$.

(iii) $\mathbf{{1}{{ {6}}^{\dfrac{ {3}}{ {4}}}}}$

Ans: The given number is ${{16}^{\dfrac{3}{4}}}$.

By the laws of indices, 

${{a}^{\dfrac{m}{n}}}=\sqrt[n]{{{a}^{m}}}$, where $a>0$.

$ {{16}^{\dfrac{3}{4}}}=\sqrt[4]{{{\left( 16 \right)}^{3}}} $

$  =\sqrt[4]{\left( 2\times 2\times 2\times 2 \right)\times \left( 2\times 2\times 2\times 2 \right)\times \left( 2\times 2\times 2\times 2 \right)} $

$  =2\times 2\times 2 $

Hence, the value of the expression ${{16}^{\dfrac{3}{4}}}$ is $8$.

${{({{a}^{m}})}^{n}}={{a}^{mn}}$, where $a>0$.

$ {{16}^{\dfrac{3}{4}}}={{(4\times 4)}^{\dfrac{3}{4}}} $

$  ={{({{4}^{2}})}^{\dfrac{3}{4}}} $ 

$ ={{(4)}^{2\times \dfrac{3}{4}}} $

$ ={{({{2}^{2}})}^{2\times \dfrac{3}{4}}} $ 

$ ={{2}^{2\times 2\times \dfrac{3}{4}}} $

$ ={{2}^{3}} $

Hence, the value of the expression is ${{16}^{\dfrac{3}{4}}}=8$.

(iv) $\mathbf{{12}{{ {5}}^{ {-}\dfrac{ {1}}{ {3}}}}}$

Ans: The given number is ${{125}^{-\dfrac{1}{3}}}$.

By the laws of indices, it is known that 

${{a}^{-n}}=\dfrac{1}{{{a}^{^{n}}}}$, where $a>0$.

Therefore, 

$ {{125}^{-\dfrac{1}{3}}}=\dfrac{1}{{{125}^{\dfrac{1}{3}}}} $

$  ={{\left( \dfrac{1}{125} \right)}^{\dfrac{1}{3}}} $

$ =\sqrt[3]{\left( \dfrac{1}{125} \right)} $

$ =\sqrt[3]{\left( \dfrac{1}{5}\times \dfrac{1}{5}\times \dfrac{1}{5} \right)} $

$ =\dfrac{1}{5}. $

Hence, the value of the expression ${{125}^{-\dfrac{1}{3}}}$ is  $\dfrac{1}{5}$.

3. Simplify and evaluate each of the expressions:

(i)$\mathbf{{{ {2}}^{\dfrac{ {2}}{ {3}}}} {.}{{ {2}}^{\dfrac{ {1}}{ {5}}}}}$

Ans: The given expression is ${{2}^{\dfrac{2}{3}}}{{.2}^{\dfrac{1}{5}}}$.

By the laws of indices, it is known that

${{a}^{m}}\cdot {{a}^{n}}={{a}^{m+n}}$, where $a>0$.

 ${{2}^{\dfrac{2}{3}}}{{.2}^{\dfrac{1}{5}}}={{(2)}^{\dfrac{2}{3}+\dfrac{1}{5}}}$

 $ ={{(2)}^{\dfrac{10+3}{15}}} $

 $ ={{2}^{\dfrac{13}{15}}}. $

Hence, the value of the expression ${{2}^{\dfrac{2}{3}}}{{.2}^{\dfrac{1}{5}}}$ is ${{2}^{\dfrac{13}{15}}}$.

(ii) ${{\left( {{\frac{ {1}}{ {{3}^3}}}} \right)}^{ {7}}}$

Ans: The given expression is  ${{\left( {{\frac{ {1}}{ {{3}^3}}}} \right)}^{ {7}}}$.

It is known by the laws of indices that,

 ${{({{a}^{m}})}^{n}}={{a}^{mn}}$, where $a>0$.

 ${{\left( {{\frac{ {1}}{ {{3}^3}}}} \right)}^{ {7}}} =\left ( \dfrac{1}{3^{21}} \right )$

Hence, the value of the expression  ${{\left( {{\frac{ {1}}{ {{3}^3}}}} \right)}^{ {7}}}$ is  $\left ( \dfrac{1}{3^{21}} \right )$

(iii) $\dfrac{ {1}{{ {1}}^{\dfrac{ {1}}{ {2}}}}}{ {1}{{ {1}}^{\dfrac{ {1}}{ {4}}}}}$

Ans: The given number is $\dfrac{{{11}^{\dfrac{1}{2}}}}{{{11}^{\dfrac{1}{4}}}}$.

It is known by the Laws of Indices that

 $\dfrac{{{a}^{m}}}{{{a}^{n}}}={{a}^{m-n}}$, where $a>0$.

$\dfrac{{{11}^{\dfrac{1}{2}}}}{{{11}^{\dfrac{1}{4}}}}={{11}^{\dfrac{1}{2}-\dfrac{1}{4}}} $

$ ={{11}^{\dfrac{2-1}{4}}} $ 

$  ={{11}^{\dfrac{1}{4}}}. $

Hence, the value of the expression $\dfrac{{{11}^{\dfrac{1}{2}}}}{{{11}^{\dfrac{1}{4}}}}$ is  ${{11}^{\dfrac{1}{4}}}$.

(iv) $\mathbf{{{ {7}}^{\dfrac{ {1}}{ {2}}}} {.}{{ {8}}^{\dfrac{ {1}}{ {2}}}}}$

Ans: The given expression is ${{7}^{\dfrac{1}{2}}}\cdot {{8}^{\dfrac{1}{2}}}$.

${{a}^{m}}\cdot {{b}^{m}}={{(a\cdot b)}^{m}}$, where $a>0$.

$ {{7}^{\dfrac{1}{2}}}\cdot {{8}^{\dfrac{1}{2}}}={{(7\times 8)}^{\dfrac{1}{2}}} $  $={{(56)}^{\dfrac{1}{2}}}. $

Hence, the value of the expression ${{7}^{\dfrac{1}{2}}}\cdot {{8}^{\dfrac{1}{2}}}$ is ${{(56)}^{\dfrac{1}{2}}}$.

Class 9 Maths Chapter 1 Solutions - Free PDF Download

The NCERT Solutions for Class 9 Maths Chapter 1, "Number Systems," serve as the first chapter of the Class 9 Maths curriculum. This chapter provides an in-depth discussion on Number Systems and their applications, starting with an introduction to whole numbers, integers, and rational numbers.

The chapter begins with an overview of Number Systems in section 1.1, followed by two crucial topics in sections 1.2 and 1.3:

Irrational Numbers : These are numbers that cannot be expressed in the form p/q.

Real Numbers and their Decimal Expansions : This section examines the decimal expansions of real numbers to differentiate between rational and irrational numbers.

Further, the chapter covers:

Representing Real Numbers on the Number Line: Solutions for two problems in Exercise 1.4 are provided.

Operations on Real Numbers: This section explores operations such as addition, subtraction, multiplication, and division involving irrational numbers.

Laws of Exponents for Real Numbers: These laws are used to solve various questions.

NCERT Solutions for Class 9 Maths Chapter 1 All Exercise

The class 9 maths chapter 1 PDF solutions by Vedantu provide a detailed and clear explanation of the concepts in the chapter. This chapter covers important topics like rational and irrational numbers, real numbers, and their decimal expansions. Understanding these foundational concepts is crucial for success in higher-level maths. When studying, focus on grasping the properties of different types of numbers and practising their operations. The solutions by Vedantu simplify these concepts with step-by-step explanations, making them easier to understand. In previous year question papers, typically 3 to 5 questions from this chapter are asked. These questions often test your understanding of number classification, representation of numbers on the number line, and converting between different forms of numbers. Therefore, practice is key to mastering this chapter and performing well in exams.

Other Related Links for CBSE Class 9 Maths Chapter 1

Chapter-Specific NCERT Solutions for Class 9 Maths

Given below are the chapter-wise NCERT Solutions for Class 9 Maths . Go through these chapter-wise solutions to be thoroughly familiar with the concepts.

FAQs on NCERT Solutions Class 9 Maths Chapter 1 - Number Systems

1. What all Comes Under the Purview of NCERT Maths Class 9 Chapter 1 Number Systems?

The subjects covered in NCERT mathematics class 9 chapter 1 Number Systems include a brief introduction to number systems using number lines, defining rational and irrational numbers using fractions, defining real numbers and declaring their decimal expansions. The chapter then returns to the number line to teach pupils how to express real numbers on it. In addition, the chapter teaches pupils how to add, subtract, multiply, and divide real numbers, or how to perform operations on real numbers. The rules of exponents for real numbers are a part of operations and are the final topic in class 9 mathematics chapter 1.

2. What are the Weightage Marks for Mathematics in Class 9?

The total mathematics paper in class 9 is 100 marks, like any other subject. Out of these 100 marks, 20 marks goes from internal assessments (pen and paper tests, multiple assessments, portfolios/project work and lab practicals for 5 marks each), and the remaining 80 marks are from the written test at the end of the school year. Out of these 80 marks, the chapter Number Systems comes for 8 marks, Algebra for 17 marks,  Coordinate Geometry for 4 marks, Geometry for 28 marks, Mensuration for 13 marks, and Statistics and Probability for 10 marks. All of these chapters’ respective marks total up to a cumulative 80 marks for the written paper.

3. How many sums are there in the NCERT Class 9 Chapter 1 Number System?

There are six exercises in the NCERT Class 9 Chapter 1 Number System. In the first exercise, Ex-1.1, there are 4 sums and in the second exercise, Ex-1.2, there are 3 sums. These first two exercises deal with the basic concepts of the number system, such as identifying the features of a rational number or an irrational number and locating them on the number line. In the third exercise, Ex-1.3, there are 9 sums, and most of them have sub-questions. The fourth exercise, Ex-1.4, comprises 2 sums, that deal with successive magnification for locating a decimal number on the number line. The fifth exercise, Ex-1.5, consists of 5 sums, on the concept of rationalization. The sixth exercise, Ex-1.6, consists of 3 sums, that have sub-questions. The sums in this exercise will require you to find the various roots of numbers.

4. Why should we download NCERT Solutions for Class 9 Maths Chapter 1?

Students should download NCERT Solutions for Class 9 Maths Chapter 1 from Vedantu (vedantu.com) to understand and learn the concepts of the Number System easily. These solutions are available free of cost on Vedantu (vedantu.com). Students must have a solid base of all concepts of Class 9 Maths if they want to score well in their exams. They can download the NCERT Solutions and other study materials such as important questions and revision notes for all subjects of Class 9. You can download these from Vedantu mobile app also.

5. Why are Class 9 Maths NCERT Solutions Chapter 1 important?

Some students find it difficult to study and score good marks in their Maths exam. They get nervous while preparing for it and goof up in their exams. However, if they utilise the best resources for studying, they can do well. This is why the Class 9 Maths NCERT Solutions Chapter 1 is important. The answers to all the questions from the back of each chapter are provided for the reference of students. 

6. Give an overview of concepts present in NCERT Solutions for Class 9 Maths Chapter 1?

The concepts in the NCERT Solutions for Class 9 Maths Chapter 1 include the introduction of number systems, rational and irrational numbers using fractions, defining real numbers, decimal expansions of real numbers, number line, representing real numbers on a number line, addition, subtraction, multiplication and division of real numbers and laws of exponents for real numbers. Chapter 1 of Class 9 Maths has a weightage of 8 marks in the final exam. 

7. Do I Need to Practice all Questions Provided in NCERT Solutions Class 9 Maths Number Systems?

Yes. Students should practice all the questions provided in the NCERT Solutions of the Number Systems chapter of Class 9 Maths, as they have been created with precision and accuracy, by expert faculty, for the students. Students can access them for free and also download them for offline use to reduce their screen time. The solutions are beneficial not only for exams but also for school homework.

8. Where can I get the NCERT Solutions for Class 9 Maths Chapter 1?

Students can download the NCERT Solutions for Class 9 Maths Chapter 1 from NCERT Solutions for Class 9 Maths Chapter 1. These are available free of cost on Vedantu (vedantu.com). These can be downloaded from the Vedantu app as well. The answers to all the questions from the 6 exercises of Chapter 1 Number Systems are provided in the NCERT Solutions. Students would also learn how to solve one question with different techniques if available. This will help them learn how to structure their answers in their Class 9 Maths exam. 

NCERT Solutions for Class 9 Maths

Ncert solutions for class 9.

NCERT Solutions for Class 9 Maths Chapter 1 Number Systems

NCERT Solutions for Class 9 Maths Chapter 1 Number Systems are provided here. Our NCERT Maths solutions contain all the questions of the NCERT textbook that are solved and explained beautifully. Here you will get complete NCERT Solutions for Class 9 Maths Chapter 1 all exercises Exercise in one place. These solutions are prepared by the subject experts and as per the latest NCERT syllabus and guidelines. CBSE Class 9 Students who wish to score good marks in the maths exam must practice these questions regularly.

Class 9 Maths Chapter 1 Number Systems NCERT Solutions

Below we have provided the solutions of each exercise of the chapter. Go through the links to access the solutions of exercises you want. You should also check out our NCERT Class 9 Solutions for other subjects to score good marks in the exams.

NCERT Solutions for Class 9 Maths Chapter 1 Exercise 1.1

NCERT Solutions for Class 9 Maths Chapter 1 Exercise 1.2

NCERT Solutions for Class 9 Maths Chapter 1 Exercise 1.3

NCERT Solutions for Class 9 Maths Chapter 1 Exercise 1.4

NCERT Solutions for Class 9 Maths Chapter 1 Exercise 1.5

NCERT Solutions for Class 9 Maths Chapter 1 Exercise 1.6

NCERT Solutions for Class 9 Maths Chapter 1 – Topic Discussion

Below we have listed the topics that have been discussed in this chapter. As Number System is one of the important topics in Maths, it has a weightage of 6 marks in class 9 Maths exams. 

• Introduction of Number Systems
• Irrational Numbers
• Real Numbers and Their Decimal Expansions
• Representing Real Numbers on the Number Line.
• Operations on Real Numbers
• Laws of Exponents for Real Numbers

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NCERT Solutions Class 9 Maths Chapter 1 Number Systems

NCERT solutions for class 9 maths chapter 1 number systems consists of an introduction about the number system and the different kinds of numbers in it. The number system has been classified into different types of numbers like natural numbers, whole numbers , integers, rational numbers, irrational numbers , etc. The NCERT solutions class 9 maths chapter 1 covers all the basics of the number system which will be helpful in forming the basic foundation of mathematics.

Class 9 maths chapter 1 number systems will help the students in differentiating between rational and irrational numbers, wherein irrational numbers cannot be expressed in the form of a ratio, and also about real numbers. Class 9 maths NCERT solutions chapter 1 number systems sample exercises can be downloaded from the links below and also you can find some of these in the exercises given below.

• NCERT Solutions Class 9 Maths Chapter 1 Ex 1.1
• NCERT Solutions Class 9 Maths Chapter 1 Ex 1.2
• NCERT Solutions Class 9 Maths Chapter 1 Ex 1.3
• NCERT Solutions Class 9 Maths Chapter 1 Ex 1.4
• NCERT Solutions Class 9 Maths Chapter 1 Ex 1.5
• NCERT Solutions Class 9 Maths Chapter 1 Ex 1.6

NCERT Solutions for Class 9 Maths Chapter 1 PDF

These NCERT solutions for class 9 maths involving the important concepts of real numbers , rational and irrational numbers, are available for free pdf download. The questions involving real numbers and their decimal form, the law of exponents are given below:

☛ Download Class 9 Maths NCERT Solutions Chapter 1 Number Systems

NCERT Class 9 Maths Chapter 1   Download PDF

NCERT Solutions for Class 9 Maths Chapter 1 Number Systems

It is advisable for the students to practice the questions in the above links as this will give them better clarity on the kind of numbers and their properties. An exercise-wise detailed analysis of NCERT Solutions Class 9 Maths Chapter 1 number systems is given below for reference.

• Class 9 Maths Chapter 1 Ex 1.1 - 4 Questions
• Class 9 Maths Chapter 1 Ex 1.2 - 4 Questions
• Class 9 Maths Chapter 1 Ex 1.3 - 9 Questions
• Class 9 Maths Chapter 1 Ex 1.4 - 2 Questions
• Class 9 Maths Chapter 1 Ex 1.5 - 5 Questions
• Class 9 Maths Chapter 1 Ex 1.6 - 11 Questions

☛ Download Class 9 Maths Chapter 1 NCERT Book

Topics Covered: The important topics focussed upon are irrational numbers, real numbers, and real numbers when expanded in the decimal form. The class 9 maths NCERT solutions chapter 1 covers the representation of real numbers on a number line, methods to perform operations on real numbers, and laws of exponents when dealing with real numbers.

Total Questions: Class 9 maths chapter 1 Number Systems consists of total 35 questions of which 30 are easy, 2 are moderate and 3 are long answer-type questions.

List of Formulas in NCERT Solutions Class 9 Maths Chapter 1

NCERT solutions class 9 maths chapter 1 covers important facts about the number systems which will help strengthen the math foundation. Like if a number ‘a’ is rational, and ‘b’ represents an irrational number, then ‘a+b’, and ‘a-b’ are irrational numbers, and ‘ab’ and ‘a/b’ are supposed to be irrational numbers, and ‘b’ is not equal to zero. For ‘a’ and ‘b’ positive real numbers the following formula or entities will be true:

• √ab = √a √b
• √(a/b) = √a / √b

Important Questions for Class 9 Maths NCERT Solutions Chapter 1

Video Solutions for Class 9 Maths NCERT Chapter 1

FAQs on NCERT Solutions Class 9 Maths Chapter 1

Do i need to practice all questions provided in ncert solutions class 9 maths number systems.

Practicing the NCERT solutions class 9 maths number systems and exercises on real numbers, rational numbers will help in exploring the number systems in a better way. The NCERT Solutions Class 9 Maths Number Systems will also provide a good insight into the solving of problems.

Why are Class 9 Maths NCERT Solutions Chapter 1 Important?

Since the number systems chapter deals with rational and irrational numbers, real numbers, and their expansion, their decimal form, also covering the law of exponents. Hence, this makes the NCERT solutions class 9 maths important for examinations.

What are the Important Formulas in NCERT Solutions Class 9 Maths Chapter 1?

There are several formulas or entities for positive real numbers which will be helpful in learning mathematics even for higher grades. Like if one wants to rationalize the denominator of 1/ ( √a + b ), then we can multiply and divide by its algebraic conjugate which is √a - b

How Many Questions are there in NCERT Solutions Class 9 Maths Chapter 1 Real Numbers?

The questions in the NCERT Solutions Class 9 Maths Chapter 1 are a great way for learning real numbers. There are around 35 questions dealing with number systems with 25 of them being simple and have straightforward logic, 6 of them are with medium complexity and 4 are elaborative questions.

What are the Important Topics Covered in NCERT Solutions Class 9 Maths Chapter 1?

The NCERT Solutions Class 9 Maths Chapter 1 deal with integers, real numbers, rational and irrational numbers. Apart from these the important topics covered are the real numbers, and what happens when they are expanded in decimal form, the law of exponents in the case of real numbers, how to differentiate between rational and irrational numbers etc.

How CBSE Students can utilize NCERT Solutions Class 9 Maths Chapter 1 effectively?

The students should first practice all the examples to understand the logic and problem solving technique and should try to solve all the exercise questions. The CBSE itself recommends the NCERT Solutions Class 9 Maths for the board exam studies.

NCERT Solutions for Class 9 Maths Chapter 1 Number Systems

Class 9 Maths Chapter 1 Solution for CBSE Board Class 9 Maths Exercise 1.1 in English Class 9 Maths Exercise 1.2 in English Class 9 Maths Exercise 1.3 in English Class 9 Maths Exercise 1.4 in English Class 9 Maths Exercise 1.5 in English

Class 9 Maths Chapter 1 Solution for State Boards Class 9 Maths Chapter 1 Exercise 1.1 Class 9 Maths Chapter 1 Exercise 1.2 Class 9 Maths Chapter 1 Exercise 1.3 Class 9 Maths Chapter 1 Exercise 1.4 Class 9 Maths Chapter 1 Exercise 1.5 Class 9 Maths Chapter 1 Exercise 1.6

Class 9 Maths Chapter 1 Solution in Hindi Class 9 Maths Exercise 1.1 in Hindi Class 9 Maths Exercise 1.2 in Hindi Class 9 Maths Exercise 1.3 in Hindi Class 9 Maths Exercise 1.4 in Hindi Class 9 Maths Exercise 1.5 in Hindi

NCERT Solutions for Class 9 Maths Chapter 1 Number Systems in Hindi Medium and English medium has been updated for academic session 2024-25. Tiwari Academy is a popular online platform that provides educational resources and solutions for students. As we continue to offer Class 9 Maths NCERT Solutions, here are some potential benefits of using Tiwari Academy for learning Class 9 Maths. Question-answers and solutions are modified as per revised NCERT book published for 2024-25 syllabus. We typically provides simple yet complete solutions to NCERT textbooks, including step-by-step explanations for each problem. This can be especially helpful for students who may find difficulty in understanding certain concepts.

All the Solutions for Class 9th Maths Chapter 1 have been updated according to latest CBSE Curriculum and NCERT Books for 2024-25. Since UP Board Students are using same NCERT Textbooks , they can also download UP Board Solutions for Class 9 Maths Chapter 1 in Hindi Medium or English Medium. Class 9 Maths NCERT Solutions have been provided by explaining the formulae and giving step by step explanation.

The content is according to the latest CBSE syllabus 2024-25 for the students of CBSE Board as well as UP Board and MP Board following the updated NCERT (https://ncert.nic.in/) Books for their final exams. Solutions for chapter 1 9th Maths are available in PDF format on our website Tiwari Academy and also through videos on Apps and website.

Study Materials on 9th Maths Chapter 1

• Study Material 9th Maths Chapter 1 for 2024-25 – English Medium
• Study Material 9th Maths Chapter 1 for 2024-25 – Hindi Medium
• Class 9 Mathematics Solutions Main Page

The topic Number Systems is the basis of Arithmetic. It is like learning the alphabets of any mathematics. We can say that 9th Maths chapter 1 is the foundation of Maths for secondary classes. CBSE NCERT Solutions for Class 9 mathematics Chapter 1 Number Systems in PDF format. These solutions are available for free download for session 2024-25. These are updated as per latest curriculum. Kindly visit the Discussion Forum and become a partner in knowledge sharing in mathematics. NCERT Solutions Offline Apps 2024-25, work without internet connection. Everything on Tiwari Academy website and Apps are available free of cost. No login or registration is required.

Important Questions on 9th Maths Chapter 1

Is zero a rational number can you write it in the form p/q, where p and q are integers and q≠0.

Yes, zero is a rational number. It can be written in the form of p/q. For example: 0/1, 0/2, 0/5 are rational numbers, where p and q are integers and q≠0.

Simplify each of the following expression: (3 + √3)(2 + √2)

(3 + √3)(2 + √2) = 6 + 3√2 + 2√3 + √6

Find six rational numbers between 3 and 4.

Six rational numbers between 3 and 4 are 3.1, 3.2, 3.3, 3.4, 3.5 and 3.6.

Express 0.99999… in the form of p/q . Are you surprised by your answer?

0.99999… Let x = 0.99999… … (i) Multiplying equation (i) by 10 both sides 10x = 9.99999… ⇒ 10x = 9 + 0.99999…… ⇒ 10x = 9 + x [From equation (i)] ⇒ 10x – x = 9 ⇒ 9x = 9 ⇒ x = 9/9 = 1 The answer makes sense as 0.99999… is very close to 1, that is why we can say that 0.99999=1.

Write three numbers whose decimal expansions are non-terminating non-recurring.

Three non-terminating non-recurring decimals: 0.414114111411114… 2.01001000100001… π=3.1416…

1. Natural numbers are those numbers which are used for counting. 2. Whole numbers are the collection of all natural numbers together with zero. 3. Integers are the collection of all whole numbers and negative of natural numbers. 4. Rational numbers are those numbers which can be expressed in the form of p/q, where p, q are integers and q is not equal to 0. 5. Irrational numbers are those numbers which cannot be expressed in the form of p/q, where p, q are integers and q is not = 0. 6. Real numbers are the collection of all rational and irrational numbers.

Two numbers are said to be equivalent, if numerators and denominators of both are in proportion or they are reducible to be equal. The decimal expansion of real numbers can be terminating or non-terminating repeating or non-terminating non-repeating. The decimal expansion of rational numbers can either be terminating or non-terminating and vice-versa. The decimal expansion of irrational numbers can either be non-recurring and vice-versa.

If a is a rational and b is an irrational, then a + b and a – b are irrational, and ab and a/b are irrational numbers, where b is not equal to 0. If a and b both are irrational, then a+b, a-b, ab and a/b may be rational or irrational. If a be any real number and n be any positive integer such that a^1/n = n√a is a real number, then ‘n’ is called exponent, a is called radical and √ is called radical sign.

How many questions in each exercise are given in chapter 1 of class 9 Maths?

There are 6 exercises in chapter 1 (Number systems) of class 9 Maths. In the first exercise (Ex 1.1), there are four questions. In the second exercise (Ex 1.2), there are four questions. In the third exercise (Ex 1.3), there are nine questions. In the fifth exercise (Ex 1.4), there are five questions. In the sixth exercise (Ex 1.5), there are three questions. So, there are in all 25 questions in chapter 1 (Number systems) of class 9 Maths. There are in all 20 examples in chapter 1 (Number systems) of class 9 Maths.

What are the core topics to study in chapter 1 Number systems of class 9 Mathematics?

In chapter 1, Number systems of class 9 Maths, students will study: 1. Natural Numbers, Whole Numbers, Integers, Rational Numbers. 2. Irrational Numbers. 3. Real Numbers and their Decimal Expansions. 4. Representing Real Numbers on the Number Line. 5. Operations on Real Numbers. 6. Laws of Exponents for Real Numbers.

Is chapter 1 of class 9th Maths difficult to solve?

Chapter 1 of class 9th Maths is not easy and not difficult. It lies in the middle of easy and difficult because some examples and questions of this chapter are easy, and some are difficult. However, the difficulty level of anything varies from student to student. So, Chapter 1 of class 9th Maths is easy or not depends on students also. Some students find it difficult, some find it easy, and some find it in the middle of easy and difficult.

How long it takes to study chapter 1 of class 9th Maths?

Students need a maximum of eight days to do chapter 1 of class 9th Maths if they give at least 2 hours per day to this chapter. This time also depends on student’s speed, efficiency, capability, and many other factors.

Chapter 2. Polynomials »

Mayank Tiwari

I have completed my B. Tech. in Computer Science and Engineering. Since, then I am working for Tiwari Academy as quality manager in content formation. I am currently Pursuing M. Tech. in Computer Science and Engineering with Specialization in Artificial Intelligence in Delhi.

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Chapter 1 Class 9 Number Systems

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Get solutions of all NCERT Questions of Chapter 1 Class 9 Number System free at teachoo. Answers to all NCERT Exercises and Examples are solved for your reference. Theory of concepts is also made for your easy understanding

In this chapter, we will learn

• Different Types of numbers like Natural Numbers, Whole numbers, Integers, Rational numbers
• How to find rational numbers between two rational numbers
• What is an irrational number
• Checking if number is irrational or not
• And how to draw an irrational number on the number line
• Then, we will study What a real number is
• And find Decimal expansions - Terminating, Non terminating - repeating, Non terminating Non repeating
• Converting non-terminating repeating numbers into p/q form
• Finding irrational numbers between two numbers
• Representing real numbers on the number line (we use magnification)
• We will learn how to add , subtract and multiply numbers with square root (like 5√2 + 3√3 - 8√2)
• We will learn some identities of numbers with square root (like (√a + √b) 2 )
• How to rationalize numbers
• We will also do questions on Law of Exponents (here, the exponents can also be in fractions)

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NCERT Solutions for Class 9 Maths Chapter 1 Number Systems

NCERT Solutions for Class 9 Maths Chapter 1 Number Systems: NCERT Solutions for Class 9 maths chapter 1 number systems begin with an introduction to the number system and the various types of numbers within it. Embibe’s expert professors have created Class 9 Maths chapter 1 NCERT solutions. These NCERT Class 9 Maths chapter 1 solutions assist students in dealing with challenges in their final exam preparation. These solutions also simplify problems so that students can understand them.

Number Systems discusses the Origin and History of Numbers, Integers, Rational Numbers, Non-Terminating, Non-Recurring Decimals, Irrational Number Properties, and many other topics. Embibe provides over 470+ practice questions for all of the subtopics covered in Chapter 1. Students must practice all of Embibe’s practice questions without fail. They can also attempt unlimited mock tests and go through the explainer videos for better understanding. Scroll down to learn more.

NCERT Solutions for Class 9 Maths Chapter 1: Important Topics

This exercise is easy to understand, and students can build fundamentals that will benefit them in the long run for entrance exams. Students will get exposed to a wide variety of problems that will help them in developing problem-solving skills. Students are advised to go through the chapter’s video lessons before moving on to problem-solving.

At Embibe, students can find the solutions to every question of this exercise. All the solutions are offered for, and students can also access NCERT 3D Videos, NCERT Exemplars , Embibe Explainers, practice questions , mock tests and so on for.

We have provided the list of topics included in this exercise below:

NCERT Solutions for Class 9 Maths Chapter 1: Points To Remember

Some of the important points related to Number Systems have been mentioned below for quick reference of students.

• Natural Numbers: These are the counting numbers (1, 2, 3,1, 2, 3, etc.).
• Whole Numbers: The set of numbers that includes all natural numbers and the number zero are called whole numbers.
• Prime Numbers: A natural number larger than 11 is a prime number if it does not have other divisors except for itself and 11. (The lowest prime number is 22. 22 is also the only even prime number. The lowest odd prime number is 33.)
• Composite Numbers: It is a natural number that has at least one divisor different from unity and itself.
• Odd Numbers: An integer that is not an even number is an odd number.
• Divisibility Tests: (i) Divisibility by 22 or 55: A number is divisible by 22 or 55 if the last digit is divisible by 22 or 55. (ii) Divisibility by 33 (or 99): All such numbers, the sum of whose digits are divisible by 33 (or 99), are divisible by 33 (or 99). (iii) Divisibility by 44: A number is divisible by 44 if the last 22 digits are divisible by 44. (iv) Divisibility by 66: A number is divisible by 66 if it is simultaneously divisible by 22 and 33. (v) Divisibility by 88: A number is divisible by 88 if the last 33 digits of the number are divisible by 88.

NCERT Solutions for Class 9 Maths: All Chapters

The detailed NCERT Class 9 Maths solutions are provided below for:

• 1st Chapter: Number Systems
• 2nd Chapter :  Polynomials
• 3rd Chapter: Coordinate Geometry
• 4th Chapter :  Linear Equations in Two Variables
• 5th Chapter :  Introduction to Euclid’s Geometry
• 6th Chapter: Lines and Angles
• 7th Chapter :  Triangles
• 8th Chapter: Quadrilaterals
• 9th Chapter: Areas of Parallelograms and Triangles
• 10th Chapter: Circles
• 11th Chapter: Constructions
• 12th Chapter: Heron’s Formula
• 13th Chapter: Surface Areas and Volumes
• 14th Chapter: Statistics
• 15th Chapter: Probability

Attempt NCERT Class 9 Maths Mock Test

Students should take mock tests for NCERT Class 9 Maths subjects. It will help them prepare for the exam better. Click on the links below to access NCERT Class 9 Maths mock tests on Embibe:

FAQs on NCERT Solutions for Class 9 Maths Chapter 1

Some of the frequently asked questions on the NCERT Solutions for 9th Maths Chapter 1 are as follows:

Ans:  The concepts are explained in simple language in the NCERT solutions for Class 9 chapter 1 Maths by Embibe. The NCERT solutions are prepared by a team of experts at Embibe to help students enhance their exam preparation.

Ans:   Students will learn that a number system is called a rational number if it can be written as p/q, the decimal expansion of a rational and irrational number, and what is a real number and so on.

Ans:  The exercises covered in NCERT chapter 1 of Class 9 Maths are as follows:  1) Exercise 1.1: 4 Questions (4 short answers)  2) Exercise 1.2: 4 Questions (4 short answers)  3) Exercise 1.3: 9 Questions (8 short answers, 1 long answer)  4) Exercise 1.4: 2 Questions (2 long answers)  5) Exercise 1.5: 5 Questions (4 short answers, 1 long answer)  6) Exercise 1.6: 3 Questions (3 short answers).

Ans:  The NCERT solutions by Embibe will help students understand the chapter better. The NCERT solutions for chapter 1 of Class 9 Maths have been explained in a step-by-step and detailed manner through videos so that any student can understand them.

Ans:  Students can get the NCERT Solutions for Class 9 Maths Chapter 1 for from Embibe, and in return, they get tricks, tips, and notes that they can revise at the last minute before the exam. This will help the students to score well.

We hope you liked this detailed article on NCERT Solutions for 9th Maths Chapter 1. For more, stay tuned to Embibe.

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Class 9 Mathematics Number System Assignments

We have provided below free printable Class 9 Mathematics Number System Assignments for Download in PDF. The Assignments have been designed based on the latest NCERT Book for Class 9 Mathematics Number System . These Assignments for Grade 9 Mathematics Number System cover all important topics which can come in your standard 9 tests and examinations. Free printable Assignments for CBSE Class 9 Mathematics Number System , school and class assignments, and practice test papers have been designed by our highly experienced class 9 faculty. You can free download CBSE NCERT printable Assignments for Mathematics Number System Class 9 with solutions and answers. All Assignments and test sheets have been prepared by expert teachers as per the latest Syllabus in Mathematics Number System Class 9. Students can click on the links below and download all Pdf Assignments for Mathematics Number System class 9 for free. All latest Kendriya Vidyalaya Class 9 Mathematics Number System Assignments with Answers and test papers are given below.

Mathematics Number System Class 9 Assignments Pdf Download

We have provided below the biggest collection of free CBSE NCERT KVS Assignments for Class 9 Mathematics Number System . Students and teachers can download and save all free Mathematics Number System assignments in Pdf for grade 9th. Our expert faculty have covered Class 9 important questions and answers for Mathematics Number System as per the latest syllabus for the current academic year. All test papers and question banks for Class 9 Mathematics Number System and CBSE Assignments for Mathematics Number System Class 9 will be really helpful for standard 9th students to prepare for the class tests and school examinations. Class 9th students can easily free download in Pdf all printable practice worksheets given below.

Topicwise Assignments for Class 9 Mathematics Number System Download in Pdf

Advantages of Class 9 Mathematics Number System Assignments

• As we have the best and largest collection of Mathematics Number System assignments for Grade 9, you will be able to easily get full list of solved important questions which can come in your examinations.
• Students will be able to go through all important and critical topics given in your CBSE Mathematics Number System textbooks for Class 9 .
• All Mathematics Number System assignments for Class 9 have been designed with answers. Students should solve them yourself and then compare with the solutions provided by us.
• Class 9 Students studying in per CBSE, NCERT and KVS schools will be able to free download all Mathematics Number System chapter wise worksheets and assignments for free in Pdf
• Class 9 Mathematics Number System question bank will help to improve subject understanding which will help to get better rank in exams

Frequently Asked Questions by Class 9 Mathematics Number System students

At https://www.cbsencertsolutions.com, we have provided the biggest database of free assignments for Mathematics Number System Class 9 which you can download in Pdf

We provide here Standard 9 Mathematics Number System chapter-wise assignments which can be easily downloaded in Pdf format for free.

You can click on the links above and get assignments for Mathematics Number System in Grade 9, all topic-wise question banks with solutions have been provided here. You can click on the links to download in Pdf.

We have provided here topic-wise Mathematics Number System Grade 9 question banks, revision notes and questions for all difficult topics, and other study material.

We have provided the best collection of question bank and practice tests for Class 9 for all subjects. You can download them all and use them offline without the internet.

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• Number Systems Class 9 Case Study Questions Maths Chapter 1

Last Updated on August 8, 2024 by XAM CONTENT

Hello students, we are providing case study questions for class 9 maths. Case study questions are the new question format that is introduced in CBSE board. The resources for case study questions are very less. So, to help students we have created chapterwise case study questions for class 9 maths. In this article, you will find case study questions for CBSE Class 9 Maths Chapter 1 Number Systems. It is a part of Case Study Questions for CBSE Class 9 Maths Series.

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Case Study Questions on Number Systems

Passage 1: Mrs. Rakhi lives in an undeveloped area where there is no facility of proper education. But one thing is available in that area i.e., network. Since she was very keen to take education, so she decided to complete her education through e-learning.

One day she was studying number system, where she learnt about rational numbers, irrational numbers and decimal numbers, etc.

On the basis of the above information, solve the following questions:

Q 1. Convert the rational number $\frac{2}{15}$ into decimal number. Q 2. Write one irrational number between 2.365 and 3.125 . Q 3. If $x+\sqrt{2}=3$, then find the value of $\frac{1}{x}$. Q4. Find the product of two irrational numbers $(7+3 \sqrt{2})$ and $(7-3 \sqrt{2})$.

Difficulty Level: Medium

2. One irrational number between 2.365 and 3.125 is 2.6121121112 . 3. We have, $x+\sqrt{2}=3$ $$ \begin{aligned} & : \frac{1}{x}=\frac{1}{3-\sqrt{2}} \times \frac{3+\sqrt{2}}{3+\sqrt{2}} \\ & \text { [by rationalisation] } \\ & =\frac{3+\sqrt{2}}{(3)^2-(\sqrt{2})^2} \\ & =\frac{3+\sqrt{2}}{9-2}=\frac{3+\sqrt{2}}{7} \end{aligned} $$ 4. $(7+3 \sqrt{2})(7-3 \sqrt{2})=(7)^2-(3 \sqrt{2})^2$ $$ \begin{aligned} & =49-18 \\ & =31 \end{aligned} $$

Coordinate Geometry Class 9 Case Study Questions Maths Chapter 3

Polynomials class 9 case study questions maths chapter 2, topics from which case study questions may be asked.

• Representation on number line
• Concept of rationalizing the denominator
• Rationalizing the denominator of expressions with square roots
• Applying the laws of exponents to simplify expressions
• Rationalizing surds

The sum or difference of a rational number and an irrational number is irrational. The product or quotient of a non-zero rational number with an irrational number is irrational .

Case study questions from the above given topic may be asked.

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Frequently Asked Questions (FAQs) on Number Systems Case Study

Q1: what is the significance of the number system in mathematics.

A1: The number system is fundamental in mathematics as it provides a systematic way to represent and work with numbers. It allows for the classification, comparison, and operation of numbers, which is essential for various mathematical concepts and real-world applications. Understanding the number system is crucial for solving problems in arithmetic, algebra, geometry, and beyond.

Q2: Are all integers also rational numbers?

A2: Yes, all integers are rational numbers because they can be expressed as a fraction where the denominator is 1. For example, 5 can be written as 5/1​, making it a rational number.

Q3: How do you convert a repeating decimal into a fraction?

A3: To convert a repeating decimal into a fraction, you can set the repeating decimal as a variable and use algebraic manipulation. For example, for $x=0.666 \ldots$: Let $x=0.666 \ldots$ Multiply both sides by 10 to shift the decimal point: $10 x=6.666 \ldots$ Subtract the original equation from this new equation: $10 x-x=6.666 \ldots-0.666 \ldots$ Simplify: $9 x=6$ Solve for $x: x=\frac{6}{9}=\frac{2}{3}$

Q4: What are the key concepts covered in Chapter 1 of CBSE Class 9 Maths regarding number systems?

A4: Chapter 1 of CBSE Class 9 Maths covers concepts such as understanding rational numbers, irrational numbers and Laws of exponents. (i) Review of representation of natural numbers and Integers on number line (ii) Rational numbers on the number line. (iii) Rational numbers as recurring/ terminating decimals (iv) Operations on real numbers. (v) Definition of nth root of a real number (vi) Law of exponents with integral powers

Q5: What is the decimal expansion of rational numbers like?

A5: The decimal expansion of rational numbers is either terminating (e.g., 0.75) or non-terminating but repeating (e.g., 0.666… $=\frac{2}{3}$).

Q6: Can a number be both rational and irrational?

A6: No, a number cannot be both rational and irrational. A rational number can be expressed as a fraction of two integers, while an irrational number cannot. They are mutually exclusive categories.

Q7: Are there any online resources or tools available for practicing number systems case study questions?

A7: We provide case study questions for CBSE Class 9 Maths on our website. Students can visit the website and practice sufficient case study questions and prepare for their exams. If you need more case study questions, then you can visit Physics Gurukul website. they are having a large collection of case study questions for all classes.

Q8: What are the important keywords for CBSE Class 9 Maths Number Systems?

A8: List of important keywords given below – Natural Numbers: Positive Counting number starting from 1. Whole Number: All natural numbers together with 0. Integers (Z): Set of all whole numbers and negative of natural numbers Rational Number: Numbers which can be expressed in p/q form, where q ≠ 0 and p and q are integers. Fraction: Numbers which can be expressed in form of p/q but are only positive Equivalent Rational Numbers: Two rational numbers are said to be equivalent, if numerator and denominators of both rational numbers are in proportion or they are reducible to be equal.

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NCERT Solutions for Class 9 Maths Chapter 1 – Number Systems

Ncert solutions for class 9 maths chapter 1 – number systems pdf.

Free PDF of NCERT Solutions for Class 9 Maths Chapter 1 – Number Systems includes all the questions provided in NCERT Books prepared by Mathematics expert teachers as per CBSE NCERT guidelines from Mathongo.com. To download our free pdf of Chapter 1 Number Systems Maths NCERT Solutions for Class 9 to help you to score more marks in your board exams and as well as competitive exams.

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NCERT Solutions for Class 9 Maths – Class 9 Maths NCERT Solutions

If you are searching for NCERT Solutions for Class 9 Maths , you have reached the correct place. LearnCBSE.in has created most accurate and detailed solutions for Class 9 Maths NCERT solutions. NCERT Class 9 Maths Solutions includes all the questions provided as per new revised syllabus in Class 9 math NCERT textbook.  You can download PDFs of Maths NCERT Solutions Class 9 without LOGIN. You can also practice Extra Questions for Class 9 Maths  on LearnCBSE.in

NCERT Class 9 Maths Solutions –  NCERT Solutions Class 9 Maths

• Chapter 1 Number systems
• Chapter 2 Polynomials
• Chapter 3 Coordinate Geometry
• Chapter 4 Linear Equations in Two Variables
• Chapter 5 Introduction to Euclid Geometry
• Chapter 6 Lines and Angles
• Chapter 7 Triangles
• Chapter 8 Quadrilaterals
• Chapter 9 Areas of Parallelograms and Triangles
• Chapter 10 Circles
• Chapter 11 Constructions
• Chapter 12 Heron’s Formula
• Chapter 13 Surface Areas and Volumes
• Chapter 14 Statistics
• Chapter 15 Probability
• Class 9 Maths (Download PDF)

There are 15 chapters in class 9 maths. These chapters lay a foundation for the chapters that will come in class 10. This pdf is accessible to everyone and they can use this pdf based on their convenience. Here below we are helping you with the overview of each and every chapter appearing in the textbook.

NCERT Solutions for Class 9 Maths Chapter 1

• Class 9 Maths Number systems Exercise 1.1
• Class 9 Maths Number systems Exercise 1.2
• Class 9 Maths Number systems Exercise 1.3
• Class 9 Maths Number systems Exercise 1.4
• Class 9 Maths Number Systems Exercise 1.5
• Class 9 Maths Number Systems Exercise 1.6
• Number Systems Class 9 Extra Questions

NCERT Solutions for Class 9 Maths Chapter 2

• Class 9 Maths Polynomials Exercise 2.1
• Class 9 Maths Polynomials Exercise 2.2
• Class 9 Maths Polynomials Exercise 2.3
• Class 9 Maths Polynomials Exercise 2.4
• Class 9 Maths Polynomials Exercise 2.5
• Polynomials Class 9 Extra Questions

NCERT Solutions for Class 9 Maths Chapter 3

• Class 9 Maths Coordinate Geometry Exercise 3.1
• Class 9 Maths Coordinate Geometry Exercise 3.2
• Class 9 Maths Coordinate Geometry Exercise 3.3
• Coordinate Geometry Class 9 Extra Questions

NCERT Solutions for Class 9 Maths Chapter 4

• Class 9 Maths Linear Equations in Two Variables Exercise 4.1
• Class 9 Maths Linear Equations in Two Variables Exercise 4.2
• Class 9 Maths Linear Equations in Two Variables Exercise 4.3
• Class 9 Maths Linear Equations in Two Variables Exercise 4.4
• Linear Equations for Two Variables Class 9 Extra Questions
• Linear Equations in Two Variables Class 9 Word Problems and Important Questions

NCERT Solutions for Class 9 Maths Chapter 5

• Class 9 Maths Introduction to Euclid Geometry Exercise 5.1
• Chapter 5 Introduction to Euclid’s Geometry Ex  5.2
• Introduction to Euclid’s Geometry Class 9 Extra Questions

NCERT Solutions for Class 9 Maths Chapter 6

• Class 9 Maths Lines and Angles Exercise 6.1
• Class 9 Maths Lines and Angles Exercise 6.2
• Class 9 Maths Lines and Angles Exercise 6.3
• Lines and Angles Class 9 Extra Questions

NCERT Solutions for Class 9 Maths Chapter 7

• Class 9 Maths Triangles Exercise 7.1
• Class 9 Maths Triangles Exercise 7.2
• Class 9 Maths Triangles Exercise 7.3
• Class 9 Maths Triangles Exercise 7.4
• Chapter 7 Triangles Ex 7.5
• Triangles Class 9 Extra Questions

NCERT Solutions for Class 9 Maths Chapter 8

• Class 9 Maths Quadrilaterals Exercise 8.1
• Class 9 Maths Quadrilaterals Exercise 8.2
• Quadrilaterals Class 9 Extra Questions
• Quadrilaterals Class 9 Maths Important Questions

NCERT Solutions for Class 9 Maths Chapter 9

• Class 9 Maths Areas of Parallelograms and Triangles Exercise 9.1
• Class 9 Maths Areas of Parallelograms and Triangles Exercise 9.2
• Class 9 Maths Areas of Parallelograms and Triangles Exercise 9.3
• Chapter 9 Areas of Parallelograms and Triangles Ex 9.4
• Areas of Parallelograms and Triangles Class 9 Extra Questions

NCERT Solutions for Class 9 Maths Chapter 10

• Class 9 Maths Circles Exercise 10.1
• Class 9 Maths Circles Exercise 10.2
• Class 9 Maths Circles Exercise 10.3
• Class 9 Maths Circles Exercise 10.4
• Class 9 Maths Circles Exercise 10.5
• Chapter 10 Circles Ex 10.6
• Circles Class 9 Extra Questions
• Circles Class 9 Maths Important Questions with Answers

NCERT Solutions for Class 9 Maths Chapter 11

• Class 9 Maths Constructions Exercise 11.1
• Class 9 Maths Constructions Exercise 11.2
• Constructions Class 9 Extra Questions
• Class 9 Maths Constructions Important Questions

NCERT Solutions for Class 9 Maths Chapter 12

• Class 9 Maths Heron’s Formula Exercise 12.1
• Class 9 Maths Heron’s Formula Exercise 12.2
• Heron’s Formula Class 9 Extra Questions
• Class 9 Areas of Parallelograms and Triangles Worksheets with Solutions

NCERT Solutions for Class 9 Maths Chapter 13

• Class 9 Maths Surface Areas and Volumes Exercise 13.1
• Class 9 Maths Surface Areas and Volumes Exercise 13.2
• Class 9 Maths Surface Areas and Volumes Exercise 13.3
• Class 9 Maths Surface Areas and Volumes Exercise 13.4
• Class 9 Maths Surface Areas and Volumes Exercise 13.5
• Class 9 Maths Surface Areas and Volumes Exercise 13.6
• Class 9 Maths Surface Areas and Volumes Exercise 13.7
• Class 9 Maths Surface Areas and Volumes Exercise 13.8
• Chapter 13 Surface Areas and Volumes Ex 13.9
• Surface Areas and Volumes Class 9 Extra Questions
• Surface Areas and Volumes Word Problems and Important Questions

NCERT Solutions for Class 9 Maths Chapter 14

• Class 9 Maths Statistics Exercise 14.1
• Class 9 Maths Statistics Exercise 14.2
• Class 9 Maths Statistics Exercise 14.3
• Class 9 Maths Statistics Exercise 14.4
• Statistics Class 9 Extra Questions
• Maths Class 9 Statistics Important Questions with solutions

NCERT Solutions for Class 9 Maths Chapter 15

• Class 9 Maths Probability Exercise 15.1
• Probability Class 9 Extra Questions
• Class 9 Probability Important Questions

Maths NCERT Solutions

In this article, we will provide you all the necessary information regarding Class 9th Maths NCERT Solutions. NCERT Maths Class 9 Textbook Solutions is solved by expert teachers provide you a strong foundation in the subject Maths. The 9th CBSE Maths Solutions are solved keeping various parameters in mind such as stepwise marks, formulas, mark distribution, etc., This in turn, helps you not to lose even a single mark.

It is important to build a strong base in maths. This is one subject that will be useful for every student irrespective of their branch. And thus we are helping you with NCERT Solutions of Class 9 Maths. This pdf can guide you to all the solutions given in the NCERT textbook along with the exercise.

Maths plays a major role in every student’s life. Working on NCERT Solutions Class 9 Maths Notes will not only help you to score good marks in the grade 9 but also helps you to clear the toughest competitive exams like JEE, NEET, JEE Advanced etc., Further it is CBSE Class 9 Maths Solutions will also be helpful to clear the exams like Olympiad, NTSE, through which you can easily avail scholarship and make your education journey hassle free. Read on to find out everything about NCERT Class 9th Maths Solutions to secure colorful marks in CBSE grade 9.

CBSE Class 9 Maths Unit Wise Weightage

NCERT Solutions for Class 9 Maths PDF Download

Browse all 9th NCERT Maths Solutions from your mobile or desktop and gain more marks in your exams. You can also go through the Chapterwise Important Questions for Class 9 Maths which will help you in extra practice and exams. This consists of 1 mark Questions, 2 Mark Numericals Questions, 3 Marks Numerical Questions, 4 Marks Questions, Word Problems, and previous year questions (VSAQ, SAQ, LAQ, and Value-Based Questions) from all chapters in class 9 maths designed according to CBSE Class 9 Maths Syllabus are laid in a sequential manner will help in scoring more marks in your Board Examinations.

Class 9 Maths Chapter 1 Number Systems

This chapter is an extension of the number line you have studied in the previous standards. You will also get know how to place various types of numbers on the number line in this chapter. A total of 6 exercises in this chapter guides you through the representation of terminating or non terminating of the recurring decimals on the number line. Along with the rational numbers, you will also learn where to put the square roots of 2 and 3 on the number line. There are also laws of rational exponents and Integral powers taught in this chapter.

Class 9 Maths Chapter 2 Polynomials

This chapter guides you through algebraic expressions called polynomial and various terminologies related to it. There is plenty to learn in this chapter about the definition and examples of polynomials, coefficient, degrees, and terms in a polynomial. Different types of polynomials like quadratic polynomials, linear constant, cubic polynomials, factor theorems, factorization theorem are taught in this chapter.

Class 9 Maths Chapter 3 Coordinate Geometry

A total of 3 exercises in this chapter will help you understand coordinate geometry in detail. Along with there are concepts like concepts of a Cartesian plane, terms, and various terms associated with the coordinate plane are learned in this chapter. You will also learn about plotting a point in the XY plane and naming process of this point.

Class 9 Maths Chapter 4 Linear Equations in Two Variables

This chapter will introduce to a new equation, ax + by + c = 0 in two variables. The questions in this chapter will be related to proving that a linear number has infinite solutions, using ba graph to plot linear equation, and justifying any point on a line. A total of 4 exercises are there for your practice and understanding.

Class 9 Maths Chapter 5 Introduction to Euclid’s Geometry

The chapter begins with the introduction of Indian geometry as it has some base in Euclid’s geometry. The Introduction of Euclid’s geometry in this chapter helps you with a process of defining geometrical terms and shapes. There are a total of 2 exercises where you will dwell into the relationship between theorems, postulates, and axioms.

Class 9 Maths Chapter 6 Lines and Angles

This chapter in the NCERT textbook also has 2 exercises in it. There are various theorems on angles and lines in this chapter that can be asked in for proof. The first theorem which will be asked for proof is “If the two lines are intersecting each other, then the vertically opposite angles formed will be equal”. Also, the second proof that is asked is, “The sum of all the angles formed in a triangle is 180°”. There are other theorems also given, but these are based on only these two theorems.

Class 9 Maths Chapter 7 Triangles

The contents in this chapter will help in understanding the congruence of triangles along with the rules of congruence. This chapter also has two theorems in it and a total of 5 exercises for students to practice. These two theorems are given as proof while the other is used in the problems or applications. Besides this, there are many properties of inequalities and triangles in this chapter for students to learn.

Class 9 Maths Chapter 8 Quadrilaterals

This chapter is very interesting for students to learn and there are only 2 exercises in it. The questions in this chapter are related to the properties related to quadrilateral and their combinations with the triangles.

Class 9 Maths Chapter 9 Areas of Triangles and Parallelogram

This chapter is important to understand the meaning of the area with this, the areas of the triangle, parallelogram, and their combinations are asked in this chapter along with their proofs. There are also examples of the an which are used as a proof of theorems in this chapter.

Class 9 Maths Chapter 10 Circles

In this chapter, you will get to learn some interesting topics like equal chords and their distance from the center, the chord of a point and angle subtended by it, angles which are subtended by an arc of a circle, and cyclic quadrilaterals. There are also theorems in this chapter which are helpful to prove questions based on quadrilaterals, triangles, and circles.

Class 9 Maths Chapter 11 Constructions

This chapter will help you learn two different categories of construction. One of them is the construction of a triangle along with its base, difference or sum of the remaining two sides, and one base angle with base angle and parameters are given. The other is the construction of bisectors for the line segments and measuring angles that include 45/60/90, etc.

Class 9 Maths Chapter 12 Heron’s Formula

This chapter joins the long list NCERT chapters that also has 2 exercises in it. In this chapter, you will be learning the concepts that are an extension of concepts related to the area of a triangle. Furthermore, you will get to learn about finding the area of triangles, quadrilaterals, and various types of polygons. Along with the, is there is also knowledge of formula for the plane figures given in the chapter.

Class 9 Maths Chapter 13 Surface Areas and Volume

Every one of you has already studied mensuration in previous standards. Thus, you must be aware of surface areas and this chapter is on that. Along with this, this chapter also has a volume of cubes, cylinders, cuboids, cones, hemispheres, and spheres. Also, in this chapter, you will get to know about the conversion of one figure into another, and comparing volumes of two figures.

Class 9 Maths Chapter 14 Statistics

In this chapter, you will get the knowledge about the descriptive statistics and the collection of data based on different aspects of life. This is useful for interpretation and stating the inferences from the data. This chapter gives the basic knowledge of the collection of data as the data is available in raw form. As you move forward and study 5 exercises you will learn about presenting data in tabular form by keeping them together in regular intervals, polygon, histogram, or bar graph drawing. You will also get to the topics like mean, median, and mode and finding the central tendency with the raw data.

Class 9 Maths Chapter 15 Probability

Probability in this book is based on the observation approach or finding the frequency. Questions in this chapter are very intuitive as they are based on daily life or day to day situations. For example, incidents like throwing dice, coin tossing, the probability for a deck of cards and simple events. If you are curious this chapter can be very interesting for you to learn and understand.

There may be a few times where you feel you are stuck and not getting the desired solutions. This is where we can you with NCERT solutions for class 9 maths. You can use this article as a reference for all the chapters in the NCERT book.

FAQs on NCERT Solutions for Class 9 Maths

1.  How do I study for the CBSE Class 9 Maths Solutions?

Practice the CBSE 9th Maths Solutions and try covering all the topics and questions carefully.

2. How could I learn Class 9 maths in an efficient and fast way?

The best way to learn fast is to solve NCERT. NCERT has few questions but has great importance in papers. If you can solve the whole NCERT with examples, you can easily score well. If you ample time try referring to RD Sharma too as it’s the best book.

3. Can I get solved math questions for the Class 9 CBSE?

Yes, you can get solved math questions for Class 9 CBSE Exams from our page. Access the direct links available on our page and download them for free of cost.

4.  Which is the best maths guide for 9th CBSE?

NCERT Solutions for Class 9 Maths will help you aid your preparation. Get a good grip over the subject by practicing more and more NCERT Solutions prevailing on our page.

5. How can I download the NCERT Solution Book for the CBSE Class 9 Maths?

Aspirants can download the CBSE Class 9 Maths NCERT Solutions by tapping on the direct links available. Lay a stronger foundation of the concepts by referring to the NCERT Solutions.

6. How long should a student of Class 9 practice math?

It’s not about the time limit. Try practicing as much as you can and revise the complete syllabus of Class 9 Maths for the exams to score well.

Now that you are provided all the necessary information regarding NCERT Solutions for class 9 Maths and we hope this detailed article on Class 9 Maths NCERT Solutions is helpful. If you have any doubt regarding this article or NCERT Class 9 Maths Solutions, leave your comments in the comment section below and we will get back to you as soon as possible.

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NCERT Solutions

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• NCERT Solutions
• NCERT Class 9
• NCERT 9 Maths
• Chapter 1: Number Systems
• Exercise 1.1

NCERT Solutions for class 9 Maths Chapter 1 - Number Systems Exercise 1.1

NCERT Solutions Class 9 Maths Chapter 1 Number Systems Exercise 1.1 are provided here. Our subject experts have prepared the NCERT Maths solutions for Class 9 chapter-wise so that it helps students to solve problems easily while using it as a reference. They also focus on creating solutions for these exercises in such a way that it is easy to understand for the students.

NCERT Solutions for Class 9 Maths Chapter 1- Number Systems Exercise 1.1

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Exercise 1.2 Solutions 4 Questions (3 long and 1 short)

Exercise 1.3 Solutions 9 Questions (9 long)

Exercise 1.4 Solutions 2 Questions (2 long)

Exercise 1.5 Solutions 5 Questions (4 long and 1 short)

Exercise 1.6 Solutions 3 Questions (3 long)

Access Answers to Maths NCERT Class 9 Chapter 1 – Number Systems Exercise 1.1

1. Is zero a rational number? Can you write it in the form p/q where p and q are integers and q ≠ 0?

We know that a number is said to be rational if it can be written in the form p/q , where p and q are integers and q ≠ 0.

Taking the case of ‘0’,

Zero can be written in the form 0/1, 0/2, 0/3 … as well as , 0/1, 0/2, 0/3 ..

Since it satisfies the necessary condition, we can conclude that 0 can be written in the p/q form, where q can either be positive or negative number.

Hence, 0 is a rational number.

2. Find six rational numbers between 3 and 4.

There are infinite rational numbers between 3 and 4.

As we have to find 6 rational numbers between 3 and 4, we will multiply both the numbers, 3 and 4, with 6+1 = 7 (or any number greater than 6)

i.e., 3 × (7/7) = 21/7

and, 4 × (7/7) = 28/7. The numbers between 21/7 and 28/7 will be rational and will fall between 3 and 4.

Hence, 22/7, 23/7, 24/7, 25/7, 26/7, 27/7 are the 6 rational numbers between 3 and 4.

3. Find five rational numbers between 3/5 and 4/5.

There are infinite rational numbers between 3/5 and 4/5.

To find out 5 rational numbers between 3/5 and 4/5, we will multiply both the numbers 3/5 and 4/5

with 5+1=6 (or any number greater than 5)

i.e., (3/5) × (6/6) = 18/30

and, (4/5) × (6/6) = 24/30

The numbers between18/30 and 24/30 will be rational and will fall between 3/5 and 4/5.

Hence, 19/30, 20/30, 21/30, 22/30, 23/30 are the 5 rational numbers between 3/5 and 4/5

4. State whether the following statements are true or false. Give reasons for your answers.

(i) Every natural number is a whole number.

Natural numbers- Numbers starting from 1 to infinity (without fractions or decimals)

i.e., Natural numbers= 1,2,3,4…

Whole numbers- Numbers starting from 0 to infinity (without fractions or decimals)

i.e., Whole numbers= 0,1,2,3…

Or, we can say that whole numbers have all the elements of natural numbers and zero.

Every natural number is a whole number; however, every whole number is not a natural number.

(ii) Every integer is a whole number.

Integers- Integers are set of numbers that contain positive, negative and 0; excluding fractional and decimal numbers.

i.e., integers= {…-4,-3,-2,-1,0,1,2,3,4…}

i.e., Whole numbers= 0,1,2,3….

Hence, we can say that integers include whole numbers as well as negative numbers.

Every whole number is an integer; however, every integer is not a whole number.

(iii) Every rational number is a whole number.

Rational numbers- All numbers in the form p/q, where p and q are integers and q≠0.

i.e., Rational numbers = 0, 19/30 , 2, 9/-3, -12/7…

All whole numbers are rational; however, all rational numbers are not whole numbers.

NCERT Solutions for Class 9 Maths Chapter 1 Number Systems Exercise 1.1 is the first exercise of Chapter 1 of Class 9 Maths. This exercise explains how to find rational numbers between two given numbers.

Key Features of NCERT Solutions for Class 9 Maths Chapter 1 – Number Systems Exercise 1.1

• These NCERT Solutions help you solve and revise all questions of Exercise 1.1.
• After going through the stepwise solutions given by our subject expert teachers, you will be able to score more marks.
• It follows NCERT guidelines which help in preparing the students accordingly.
• It contains all the important questions from the examination point of view.

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