NCERT Solutions for Class 9 Maths Chapter 1 Number Systems

NCERT Solutions for Class 9 Maths Chapter 1 Number Systems

Komal MiglaniUpdated on 29 Aug 2025, 12:32 PM IST

Imagine you return from the grocery store and see that you forgot to buy 3 out of 10 things your mother asked you to buy. Or, during the calculation of your savings at the end of the month, you wonder if the spending is greater than your pocket money. Or checking the current temperature on your phone. These are all examples of various forms of numbers like fractions, negative, positive, etc., and in Class 9 Maths NCERT chapter 1, students will get to know more about the number systems. In this chapter, we will study rational and irrational numbers, real numbers and the operations and laws of exponents of real numbers. These NCERT Solutions for Class 9 Maths provide a clear understanding of real numbers, helping in concept clarity and exam preparation.

This Story also Contains

  1. Number Systems Class 9 Questions And Answers PDF Free Download
  2. NCERT Solutions for Class 9 Maths Chapter 1: Exercise Questions
  3. Number System Class 9 NCERT solutions: Exercise-wise
  4. Class 9 Maths NCERT Chapter 1: Extra Question
  5. Number Systems Class 9 Chapter 1: Topics
  6. Number Systems Class 9 Solutions - Important Formulae
  7. Approach to Solve Questions of Number System Class 9
  8. NCERT Solutions for Class 9 Mathematics: Chapter-wise
NCERT Solutions for Class 9 Maths Chapter 1 Number Systems
NCERT Solutions for Class 9 Maths Chapter 1 Number Systems

Numbers are everywhere, and without them, our daily lives are incomplete. These NCERT Solutions for Class 9 are trustworthy and reliable, as they are created by subject matter experts at Careers360, making them an essential resource for exam preparation. Additionally, after analysing these solutions, students can practice various methods for converting decimals and applying exponents effectively. Many toppers rely on NCERT Solutions since they are designed as per the latest syllabus. Explore solved examples, exercise solutions, notes, and syllabus at the NCERT article.

Number Systems Class 9 Questions And Answers PDF Free Download

These NCERT Solutions for Class 9 Maths Chapter 1 Number Systems have been prepared by Careers360 experts to make learning simpler and to help you score better in exams. You can also download the solutions in PDF format.

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NCERT Solutions for Class 9 Maths Chapter 1: Exercise Questions

Class 9 Maths Chapter 1 Question Answers: Exercise: 1.1
Total Questions: 4
Page number: 5

Question 1: Is zero a rational number? Can you write it in the form $\frac{p}{q}$, where p and q are integers and q ≠ 0?

Answer:

Any number that can represent in the form of $\frac{p}{q}$
$(where \ q \neq 0)$ is a rational number

Now, we can write 0 in the form of $\frac{p}{q}$
for eg. $\frac{0}{1},\frac{0}{2},\frac{0}{-1}$ etc.

Therefore, 0 is a rational number.

Question 2: Find six rational numbers between 3 and 4.

Answer:

There is an infinite number of rational numbers between 3 and 4. One way to take them is$\Rightarrow 3 = \frac{21}{7} $ and $ 4 = \frac{28}{7}$
Therefore, six rational numbers between 3 and 4 are $\frac{22}{7}, \frac{23}{7},\frac{24}{7},\frac{25}{7},\frac{26}{7},\frac{27}{7}.$

Question 3: Find five rational numbers between $\frac{3}{5}$ and $\frac{4}{5}$ .

Answer:

We can write
$\Rightarrow \frac{3}{5}= \frac{3\times 6}{5\times 6} = \frac{18}{30}$
And
$\Rightarrow \frac{4}{5}= \frac{4\times 6}{5\times 6} = \frac{24}{30}$
Therefore, five rational numbers between $\frac{3}{5}$ and $\frac{4}{5}$ are $\frac{19}{30},\frac{20}{30},\frac{21}{30},\frac{22}{30},\frac{23}{30}.$

Question 4: (i) State whether the following statements are true or false. Give reasons for your answers.
(i)Every natural number is a whole number.

Answer:

(i) TRUE
The numbers that start from 1, i.e 1, 2, 3, 4, 5, 6, .................. are natural numbers.
The numbers that start from 0, i.e, 0, 1, 2, 3, 4, 5,..., are whole numbers.
Therefore, we can clearly see that the collection of whole numbers contains all natural numbers.

Question 4: (i) State whether the following statements are true or false. Give reasons for your answers.
(ii) Every integer is a whole number.

Answer:

(ii) FALSE
Integers may be negative or positive, but whole numbers are always positive.
For eg, -1 is an integer but not a whole number.

Question 4: (i) State whether the following statements are true or false. Give reasons for your answers.
(iii) Every rational number is a whole number.

Answer:

(iii) FALSE
Numbers that can be represented in the form of $\frac{p}{q}$
(where $q \neq 0)$ are a rational number.
And numbers that start from 0, i.e., 0,1,2,3,4,......... are whole numbers.
Therefore, we can clearly see that every rational number is not a whole number.
for eg. $\frac{3}{4}$ is a rational number but not a whole number

Class 9 Maths Chapter 1 Question Answers: Exercise: 1.2
Total Questions: 3
Page number: 8

Question 1: (i) State whether the following statements are true or false. Justify your answers.
(i) Every irrational number is a real number.

Answer:

(i) TRUE
Since the real numbers are the collection of all rational and irrational numbers.

Question 1: (i) State whether the following statements are true or false. Justify your answers.
(ii) Every point on the number line is of the form $\sqrt{m}$, where m is a natural number.

Answer:

(ii) FALSE
Because negative numbers are also present on the number line, and no negative number can be the square root of any natural number

Question 1: (i) State whether the following statements are true or false. Justify your answers.
(iii) Every real number is an irrational number.

Answer:

(iii) FALSE
Real numbers include both rational and irrational numbers. Therefore, every real number is not an irrational number.

For eg, 4 is a real number but not an irrational number.

Question 2: Are the square roots of all positive integers irrational? If not, give an example of the square root of a number that is a rational number.

Answer:

NO, the Square root of all positive integers is not irrational. For the eg square of 4 is 2, which is a rational number.

Question 3: Show how $\sqrt{5}$ can be represented on the number line.

Answer:

We know that
$\sqrt{5} = \sqrt{(2)^2+(1)^2}$
Now,
1639723473448
Let OA be a line of length 2 units on the number line.
Now, construct AB of unit length perpendicular to OA. and join OB.
Now, in right angle triangle OAB, by Pythagoras theorem
$OB = \sqrt{(2)^2+(1)^2}=\sqrt{5}$
Now, take O as the centre and OB as the radius, and draw an arc intersecting the number line at C.
Point C represents $\sqrt{5}$ on a number line.

Class 9 Maths Chapter 1 Question Answers: Exercise: 1.3
Total Questions: 9
Page number: 14

Question 1: (i) Write the following in decimal form and say what kind of decimal expansion each has : (i) $\frac{36}{100}$

Answer:

We can write $\frac{36}{100}$ as
$\Rightarrow \frac{36}{100}= 0.36$
Since the decimal expansion ends after a finite number of steps. Hence, it is terminating

Question 1: (ii) Write the following in decimal form and say what kind of decimal expansion each has : (ii) $\frac{1}{11}$

Answer:

We can rewrite $\frac{1}{11}$ as

$\Rightarrow \frac{1}{11}= 0.09090909..... = 0.\overline{09}$
Since decimal expansion repeats itself,
So, it is a non-terminating recurring decimal expansion.

Question 1: (iii) Write the following in decimal form and say what kind of decimal expansion each has : (iii) $4\frac{1}{8}$

Answer:

We can rewrite $4\frac{1}{8}$ as

$\Rightarrow 4\frac{1}{8} = \frac{33}{8}= 4.125$
Since the decimal expansion ends after a finite number.
Therefore, it is terminating.

Question 1: (iv) Write the following in decimal form and say what kind of decimal expansion each has: (iv) $\frac{3}{13}$

Answer:

We can rewrite $\frac{3}{13}$ as

$\Rightarrow \frac{3}{13} = 0.230769230769 = 0.\overline{230769}$
Since decimal expansion repeats itself,
So, it is a non-terminating recurring decimal expansion.

Question 1: (v) Write the following in decimal form and say what kind of decimal expansion each has: (v) $\frac{2}{11}$

Answer:

We can rewrite $\frac{2}{11}$ as

$\Rightarrow \frac{2}{11} = 0.181818......= 0.\overline{18}$
Since decimal expansion repeats itself so it is a non-terminating recurring decimal expansion.

Question 1: (vi) Write the following in decimal form and say what kind of decimal expansion each has : (vi) $\frac{329}{400}$

Answer:

We can rewrite $\frac{329}{400}$ as

$\Rightarrow \frac{329}{400}= 0.8225$
Since decimal expansion ends after a finite no. of figures.
Hence, it is terminating.

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

Answer:

It is given that $\frac{1}{7}=0.\overline{142857}$

Therefore,

$\Rightarrow \frac{2}{7} = 2\times \frac{1}{7} = 2 \times 0.\overline{142857}= 0.\overline{285714}$

Similarly,

$\Rightarrow \frac{3}{7} = 3\times \frac{1}{7} = 3 \times 0.\overline{142857}= 0.\overline{428571}$

$\Rightarrow \frac{4}{7} = 4\times \frac{1}{7} = 4 \times 0.\overline{142857}= 0.\overline{571428}$

$\Rightarrow \frac{5}{7} = 5\times \frac{1}{7} = 5 \times 0.\overline{142857}= 0.\overline{714285}$

$\Rightarrow \frac{6}{7} = 6\times \frac{1}{7} = 6 \times 0.\overline{142857}= 0.\overline{857142}$

Question 3: (i) Express the following in the form $\frac{p}{q}$, where p and q are integers and q ≠ 0. (i) $0.\bar{6}$

Answer:

Let $x = 0.\overline6= 0.6666....$ -(i)

Now, multiply by 10 on both sides,

$10x= 6.6666...$

$\Rightarrow 10x = 6 + x$ (using (i))

$\Rightarrow 9x = 6$

$\Rightarrow x = \frac{6}{9} = \frac{2}{3}$

Therefore, $\frac{p}{q}$ form of $0.\bar{6}$ is $\frac{2}{3}$.

Question 3: (ii) Express the following in the form $\frac{p}{q}$, where p and q are integers and q ≠ 0. (ii) $0.4\bar{7}$

Answer:

We can write $0.4\overline7$ as

$\Rightarrow 0.4\overline7 = \frac{4}{10}+ \frac{0.777..}{10}$ -(i)

Now,

Let $x = 0.\overline7= 0.7777....$ -(ii)

Now, multiply by 10 on both sides,

$10x= 7.7777...$

$\Rightarrow 10x = 7 + x$ (using (ii))

$\Rightarrow 9x = 7$

$\Rightarrow x = \frac{7}{9}$
Now, put the value of x in equation (i), We will get,

$\Rightarrow 0.4\overline7 = \frac{4}{10}+ \frac{7}{10\times 9}= \frac{4}{10}+ \frac{7}{90} = \frac{36+7}{90} = \frac{43}{90}$

Therefore, $\frac{p}{q}$ form of $0.4\overline7$ is $\frac{43}{90}$

Question 3: (iii) Express the following in the form $\frac{p}{q}$, where p and q are integers and q ≠ 0. (iii) $0.\overline{001}$

Answer:

Let $x = 0.\overline{001}= 0.001001....$ -(i)

Now, multiply by 1000 on both sides.

$1000x= 1.001001...$

$\Rightarrow 1000x = 1 + x $ (using (i))

$\Rightarrow 999x = 1$

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

Therefore, $\frac{p}{q}$ form of $0.\overline{001}$ is $\frac{1}{999}$

Question 4: Express 0.99999 .... in the form $\frac{p}{q}$. Are you surprised by your answer?

Answer:

Let $x = 0.\overline{9}= 0.9999....$ -(i)

Now, multiply by 10 on both sides.

$10x= 9.999....$

$\Rightarrow 10x = 9 + x$ (using (i))

$\Rightarrow 9x = 9$

$\Rightarrow x = \frac{9}{9} = 1$

Therefore, $\frac{p}{q}$ form of $0.999....$ is 1

The difference between 1 and 0.999999 is 0.000001, which is almost negligible.

Therefore, 0.999 is much closer to 1. Hence, we can write 0.999999.... as 1

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

Answer:

We can rewrite $\frac{1}{17}$ as
$\Rightarrow \frac{1}{17} = 0.05882352941176470588235294117647= 0.\overline{0588235294117647}$
Therefore, there are a total 16 number of digits in the repeating block of digits in the decimal expansion of $\frac{1}{17}$

Question 6: Look at several examples of rational numbers in the form $\frac{p}{q}$ (q ≠ 0), 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?

Answer:

We can observe that when q is 2, 4, 5, 8, 10…
Then the decimal expansion is terminating. For example:

$\frac{3}{2}= 1.5$ , denominator $q = 2^1$

$\frac{8}{5}= 1.6$ , denominator $q = 5^1$

$\frac{15}{10} = 1.5$ , denominator $q =10=2\times 5= 2^1 , 5^1$

Therefore,

It can be observed that the terminating decimal can be obtained in a condition where prime factorization of the denominator of the given fractions has the power of 2 only or 5 only, or both.

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

Answer:

Three numbers whose decimal expansions are non-terminating non-recurring are
1) 0.02002000200002......
2) 0.15115111511115.......
3) 0.27227222722227.......

Question 8: Find three different irrational numbers between the rational numbers $\frac{5}{7}$ and $\frac{9}{11}$ .

Answer:

We can write $\frac{5}{7}$ as

$\Rightarrow \frac{5}{7} = 0.714285714285.... = 0.\overline{714285}$

And $\frac{9}{11}$ as

$\Rightarrow \frac{9}{11} = 0.818181.... = 0.\overline{81}$
Therefore, three different irrational numbers between the rational numbers $\frac{5}{7}$ and $\frac{9}{11}$ are

1) 0.72737475....
2) 0.750760770780...
3) 0.790780770760....

Question 9: (i) Classify the following numbers as rational or irrational: $\sqrt{23}$

Answer:

We can rewrite $\sqrt{23}$ in decimal form as

$\Rightarrow \sqrt{23} = 4.7958152....$

Now, as the decimal expansion of this number is non-terminating and non-recurring.

Therefore, it is an irrational number.

Question 9: (ii) Classify the following numbers as rational or irrational: $\sqrt{225}$

Answer:

We can rewrite $\sqrt{225}$ as

$\Rightarrow \sqrt{225} = 15$
We can clearly see that it is a rational number because we can represent it in $\frac{p}{q}$ form

Question 9: (iii) Classify the following numbers as rational or irrational: 0.3796

Answer:

We can rewrite 0.3796 as

$\Rightarrow 0.3796 = \frac{3796}{10000}$
Now, we can clearly see that it is a rational number as the decimal expansion of this number is terminating, and we can also write it in $\frac{p}{q}$ form.

Question 9: (iv) Classify the following numbers as rational or irrational: 7.478478....

Answer:

We can rewrite 7.478478.... as

$\Rightarrow 7.478478.... = 7.\overline{478}$
Now, as the decimal expansion of this number is non-terminating recurring. Therefore, it is a rational number.

Question 9: (v) Classify the following numbers as rational or irrational: 1.101001000100001...

Answer:

In the case of number 1.101001000100001...
As the decimal expansion of this number is non-terminating and non-repeating.
Therefore, it is an irrational number.

Class 9 Maths Chapter 1 Question Answers: Exercise: 1.4
Total Questions: 5
Page number: 20-21

Question 1: (i) Classify the following numbers as rational or irrational: $2-\sqrt{5}$

Answer:

Value of $\sqrt{5}$ is 2.23606798....
Now,
$\Rightarrow 2 - \sqrt{5} = 2 - 2.23606798... = -0.23606798...$
Now,
Since the number is in non-terminating non-recurring.
Therefore, it is an irrational number.

Question 1: (ii) Classify the following numbers as rational or irrational: $\left ( 3+\sqrt{23} \right )-\sqrt{23}$

Answer:

Given number is $\left ( 3+\sqrt{23} \right )-\sqrt{23}$

$\Rightarrow \left ( 3+\sqrt{23} \right )-\sqrt{23} = 3+\sqrt{23}-\sqrt{23} = 3$
Now, it is clearly a rational number because we can represent it in the form of $\frac{p}{q}$

Question 1: (iii) Classify the following numbers as rational or irrational: $\frac{2\sqrt{7}}{7\sqrt{7}}$

Answer:

Given number is $\frac{2\sqrt{7}}{7\sqrt{7}}$

$\Rightarrow \frac{2\sqrt{7}}{7\sqrt{7}} = \frac{2}{7}$
As we can clearly see that it can be represented in $\frac{p}{q}$ form. Therefore, it is a rational number.

Question 1: (iv) Classify the following numbers as rational or irrational: $\frac{1}{\sqrt{2}}$

Answer:

Given number is $\frac{1}{\sqrt{2}}$

$\Rightarrow \frac{1}{\sqrt{2}}= \frac{\sqrt{2}}{2}=\frac{1.41421356..}{2} =0.7071068...$
Now,
The decimal expansion of this expression is non-terminating and non-recurring.
Therefore, it is an irrational number.

Question 1: (v) Classify the following numbers as rational or irrational: $2\pi$

Answer:

Given number is $2\pi$
We know that the value of $\pi = 3.14159265...$
Now,
$\Rightarrow 2\pi = 2\times 3.14159265... = 6.2831853...$
Now,
The decimal expansion of this expression is non-terminating and non-recurring.
Therefore, it is an irrational number.

Question 2: (i) Simplify each of the following expressions: $(3+\sqrt{3})(2+\sqrt{2})$

Answer:

Given number is $(3+\sqrt{3})(2+\sqrt{2})$

Now, we will reduce it into

$\Rightarrow (3+\sqrt{3})(2+\sqrt{2})$

$= 3.2+3.\sqrt{2}+\sqrt{3}.2+\sqrt{3}.\sqrt{2}$

$= 6+3\sqrt{2}+2\sqrt{3}+\sqrt{6}$

Therefore, answer is $6+3\sqrt{2}+2\sqrt{3}+\sqrt{6}$

Question 2: (ii) Simplify each of the following expressions: $\left (3+\sqrt{3} \right )\left ( 3-\sqrt{3} \right )$

Answer:

The given number is

$\left (3+\sqrt{3} \right )\left ( 3-\sqrt{3} \right )$
Now, we will reduce it into
$\Rightarrow (3+\sqrt{3})(3-\sqrt{3})$
$= \left ( (3)^2-(\sqrt{3})^2 \right )$ Using $\left ( \ (a+b)(a-b)=a^2-b^2 \right )$
$=9 - 3 = 6$
Therefore, the answer is 6.

Question 2: (iii) Simplify each of the following expressions: $\left (\sqrt{5}+\sqrt{2} \right )^{2}$

Answer:

Given number is $\left (\sqrt{5}+\sqrt{2} \right )^{2}$
Now, we will reduce it into$\Rightarrow \left (\sqrt{5}+\sqrt{2} \right )^{2}$
$= \left ( (\sqrt{5})^2+(\sqrt{2})^2+2.\sqrt{5}.\sqrt{2} \right )$ Uisng $\left (\ (a+b)^2=a^2+b^2 +2ab\right )$
$=5+2+2\sqrt{10}$
$=7+2\sqrt{10}$

Therefore, the answer is $7+2\sqrt{10}$

Question 2: (iv) Simplify each of the following expressions: $\left (\sqrt{5}-\sqrt{2} \right )\left ( \sqrt{5}+\sqrt{2} \right )$

Answer:

Given number is $\left (\sqrt{5}-\sqrt{2} \right )\left ( \sqrt{5}+\sqrt{2} \right )$
Now, we will reduce it to
$= \left (\sqrt{5}-\sqrt{2} \right )\left ( \sqrt{5}+\sqrt{2} \right )$
$= \left ( (\sqrt{5})^2-(\sqrt{2})^2 \right )$ Using $\left ( \ (a+b)(a-b)=a^2-b^2\right )$
$=5-2$
$=3$
Therefore, the answer is 3.

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

Answer:

There is no contradiction.
When we measure a length with a scale or any other instrument, we only obtain an approximate rational value.
We never obtain an exact value.
For this reason, we cannot say that either c or d is irrational.
Therefore, the fraction $\frac{c}{d}$ is irrational.
Hence, the value of $\pi$ is approximately equal to $\frac{22}{7} = 3.142857....$

Therefore, $\pi$ is irrational.

Question 4: Represent $\sqrt{9.3}$ on the number line.

Answer:

1639723609742
Draw a line segment OB of 9.3 units.
Then, extend it to C so that BC = 1 unit.
Find the mid-point D of OC and draw a semi-circle on OC while taking D as its centre and OD as the radius.
Now, draw a perpendicular to line OC passing through point B and intersecting the semi-circle at E.
Now, take B as the centre and BE as the radius,
draw an arc intersecting the number line at F.
The length BF is $9\sqrt{3}$ units.

Question 5: (i) Rationalise the denominators of the following: $\frac{1}{\sqrt{7}}$

Answer:

Given number is $\frac{1}{\sqrt{7}}$

Now, on rationalisation, we will get,

$\Rightarrow \frac{1}{\sqrt 7} = \frac{1}{\sqrt 7}\times \frac{\sqrt 7}{\sqrt 7 } = \frac{\sqrt7}{7}$

Therefore, the answer is $\frac{\sqrt7}{7}$.

Question 5: (ii) Rationalise the denominators of the following: $\frac{1}{\sqrt{7}-\sqrt{6}}$

Answer:

Given number is $\frac{1}{\sqrt{7}-\sqrt{6}}$

Now, on rationalisation, we will get

$= \frac{1}{\sqrt 7-\sqrt6}$

$ = \frac{1}{\sqrt 7-\sqrt 6}\times \frac{\sqrt 7+\sqrt 6 }{\sqrt 7+\sqrt 6 }$

$ = \frac{\sqrt7+\sqrt 6}{(\sqrt7)^2-(\sqrt6)^2} $

$= \frac{\sqrt7+\sqrt6}{7-6}$

$= \sqrt7+\sqrt6$

Therefore, the answer is $\sqrt7+\sqrt6$.

Question 5: (iii) Rationalise the denominators of the following: $\frac{1}{\sqrt{5}+\sqrt{2}}$

Answer:

Given number is $\frac{1}{\sqrt{5}+\sqrt{2}}$

Now, on rationalisation, we will get

$= \frac{1}{\sqrt 5+\sqrt2}$

$= \frac{1}{\sqrt 5+\sqrt 2}\times \frac{\sqrt 5-\sqrt 2 }{\sqrt 5-\sqrt 2 }$

$ = \frac{\sqrt5-\sqrt 2}{(\sqrt5)^2-(\sqrt2)^2} $

$= \frac{\sqrt5-\sqrt2}{5-2}$

$= \frac{\sqrt5-\sqrt2}{3}$

Therefore, the answer is $\frac{\sqrt5-\sqrt2}{3}$

Question 5: (iv) Rationalise the denominators of the following: $\frac{1}{\sqrt{7}-2}$

Answer:

Given number is $\frac{1}{\sqrt{7}-2}$

Now, on rationalisation, we will get

$= \frac{1}{\sqrt 7-2}$

$= \frac{1}{\sqrt 7- 2}\times \frac{\sqrt 7+ 2 }{\sqrt 7+ 2 } $

$= \frac{\sqrt7+ 2}{(\sqrt7)^2-(2)^2} $

$= \frac{\sqrt7+2}{7-4}$

$= \frac{\sqrt7+2}{3}$

Therefore, answer is $\frac{\sqrt7+2}{3}$

Class 9 Maths Chapter 1 Question Answers: Exercise: 1.5
Total Questions: 3
Page number: 23

Question 1: (i) Find : $64^{\frac{1}{2}}$

Answer:

Given number is $64^{\frac{1}{2}}$

Now, on simplifying it, we will get,

$\Rightarrow 64^{\frac{1}{2}} = (8^2)^\frac{1}{2} = 8$

Therefore, the answer is 8.

Question 1: (ii) Find : $32^{\frac{1}{5}}$

Answer:

Given number is $32^{\frac{1}{5}}$

Now, on simplifying it, we will get,

$\Rightarrow 32^{\frac{1}{5}} = (2^5)^\frac{1}{5} = 2$

Therefore, the answer is 2.

Question 1: (iii) Find : $125^{\frac{1}{3}}$

Answer:

Given number is $125^{\frac{1}{3}}$

Now, on simplifying it, we will get,

$\Rightarrow 125^{\frac{1}{3}} = (5^3)^\frac{1}{3} = 5$

Therefore, the answer is 5.

Question 2: (i) Find : $9^{\frac{3}{2}}$

Answer:

Given number is $9^{\frac{3}{2}}$

Now, on simplifying it, we will get,

$\Rightarrow 9^{\frac{3}{2}} = (3^2)^\frac{3}{2} = 3^3 = 27$

Therefore, the answer is 27.

Question 2: (ii) Find : $32^{\frac{2}{5}}$

Answer:

Given number is $32^{\frac{2}{5}}$

Now, on simplifying it, we will get,

$\Rightarrow 32^{\frac{2}{5}} = (2^5)^\frac{2}{5} = 2^2 = 4$

Therefore, the answer is 4.

Question 2: (iii) Find : $16^{\frac{3}{4}}$

Answer:

Given number is $16^{\frac{3}{4}}$

Now, on simplifying it, we will get,

$\Rightarrow 16^{\frac{3}{4}} = (2^4)^\frac{3}{4} = 2^3 = 8$

Therefore, the answer is 8.

Question 2: (iv) Find : $125^{\frac{-1}{3}}$

Answer:

Given number is $125^{\frac{-1}{3}}$

Now, on simplifying it, we will get

$\Rightarrow 125^{\frac{-1}{3}} = (5^3)^\frac{-1}{3} = 5^{-1} = \frac{1}{5}$
Therefore, the answer is $\frac{1}{5}$.

Question 3: (i) Simplify : $2^{\frac{2}{3}}.2^{\frac{1}{5}}$

Answer:

Given number is $2^{\frac{2}{3}}.2^{\frac{1}{5}}$

Now, on simplifying it, we will get,

$\Rightarrow 2^{\frac{2}{3}}.2^{\frac{1}{5}} = 2^{\frac{2}{3}+\frac{1}{5}} = 2^{\frac{10+3}{15}} = 2^\frac{13}{15}$
$\left ( \because a^n.a^m = a^{n+m} \right )$

Therefore, the answer is $2^{\frac{13}{15}}$.

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

Answer:

Given number is $\left (\frac{1}{3^{3}} \right )^{7}$

Now, on simplifying it, we will get,

$\Rightarrow \left ( \frac{1}{3^3} \right )^7= \frac{1^7}{3^{3\times7}} = \frac{1}{3^{21}} = 3^{-21}$
$\left ( \because (a^n)^m = a^{n.m} \ and \ \frac{1}{a^m}= a^{-m}\right )$

Therefore, the answer is $3^{-21}$.

Question 3: (iii) Simplify : $\frac{11^{\frac{1}{2}}}{11^{\frac{1}{4}}}$

Answer:

Given number is $\frac{11^{\frac{1}{2}}}{11^{\frac{1}{4}}}$

Now, on simplifying it, we will get,

$\Rightarrow \frac{11^{\frac{1}{2}}}{11^{\frac{1}{4}}} = 11^{\frac{1}{2}-\frac{1}{4}}= 11^{\frac{2-1}{4}} = 11^\frac{1}{4}$
$\left ( \because \frac{a^n}{a^m}= a^{n-m}\right )$
Therefore, the answer is $11^{\frac{1}{4}}$.

Question 3: (iv) Simplify : $7^{\frac{1}{2}}.8^{\frac{1}{2}}$

Answer:

Given number is $7^{\frac{1}{2}}.8^{\frac{1}{2}}$

Now, on simplifying it, we will get,

$\Rightarrow 7^{\frac{1}{2}}.8^{\frac{1}{2}}= (7\times8)^{\frac{1}{2}} = 56^{\frac{1}{2}}$
$\left ( \because a^n.b^n=(a.b)^n\right )$
Therefore, the answer is $56^{\frac{1}{2}}$.

Number System Class 9 NCERT solutions: Exercise-wise

Exercise-wise NCERT Solutions of Number Systems Class 9 Maths Chapter 1 are provided in the links below.

Class 9 Maths NCERT Chapter 1: Extra Question

Question: Simplify: $ \left(\frac{5}{2}\right)^3 \times \left(\frac{2}{5}\right)^2 $

Answer:

$\left(\frac{5}{2}\right)^3 = \frac{5^3}{2^3} = \frac{125}{8}, \quad \left(\frac{2}{5}\right)^2 = \frac{2^2}{5^2} = \frac{4}{25}$

$\frac{125}{8} \times \frac{4}{25} = \frac{125 \times 4}{8 \times 25} = \frac{500}{200} = \frac{5}{2}$

Number Systems Class 9 Chapter 1: Topics

The topics discussed in the NCERT Solutions for class 9 Maths chapter 1 Number Systems are:

  • Introduction
  • Irrational Numbers
  • Real Numbers and Their Decimal Expansions
  • Operations on Real Numbers
  • Laws of Exponents for Real Numbers

Number Systems Class 9 Solutions - Important Formulae

Any unique real number can be represented on a number line.

If r = rational number and s = irrational number

Then (r + s), (r – s), (r × s), and ($\frac rs$) are all irrational.

Rules for positive real numbers:

  • (i) $\sqrt{a b}=\sqrt{a} \sqrt{b}$
  • (ii) $\sqrt{\frac{a}{b}}=\frac{\sqrt{a}}{\sqrt{b}}$
  • (iii) $(\sqrt{a}+\sqrt{b})(\sqrt{a}-\sqrt{b})=a-b$
  • (iv) $(a+\sqrt{b})(a-\sqrt{b})=a^2-b$
  • (v) $(\sqrt{a}+\sqrt{b})^2=a+2 \sqrt{a b}+b$

To rationalise the denominator of $\frac{1}{\sqrt{a}+b}$, we multiply this by $\frac{\sqrt{a}-b}{\sqrt{a}-b}$, where $a$ and $b$ are integers.

Let $a>0$ be a real number and $p$ and $q$ be rational numbers. Then,
(i) $a^p \cdot a^q=a^{p+q}$
(ii) $\left(a^p\right)^q=a^{p q}$
(iii) $\frac{a^p}{a^q}=a^{p-q}$
(iv) $a^p b^p=(a b)^p$

Approach to Solve Questions of Number System Class 9

Given below are useful strategies to access and use the Number Systems Class 9 NCERT Solutions effectively:

  • Understand types of numbers: The study should begin with natural numbers and whole numbers, followed by integers, rational numbers, and irrational numbers to construct knowledge for advanced learning.
  • Learn how to represent numbers on the number line: Using number lines for visually showing rational numbers together with irrational numbers teaches students how real numbers function with density and continuous distribution.
  • Work on rational and irrational number properties: Students should familiarise themselves with the methods to identify numbers as rational or irrational entities while understanding operational behaviours.
  • Use laws of exponents for real numbers: Efficient number simplification occurs through applying exponent laws when working with rational and irrational numbers during expression solutions.
  • Practice converting decimals to fractions: Students should demonstrate total mastery in converting recurring and terminating decimals into rational form because this skill appears in both school tests and competitive examinations.
  • Apply real number operations: Practice numerous examples, including real number addition, subtraction, multiplication and division, until fully mastering number operational skills.

Frequently Asked Questions (FAQs)

Q: Which are the most difficult chapters of NCERT Class 9 Maths syllabus?
A:

Most of the students consider geometry, especially triangles, as the most difficult chapter in the NCERT Class 9 Maths syllabus. Students can also refer to the NCERT exemplar questions after completing the NCERT textbook for further practice purposes.

Q: Does CBSE provides the solutions of NCERT textbook for Class 9 Maths?
A:

No, CBSE doesn’t provide NCERT solutions for any class or subject. But many trusted educational websites, such as Careers360, provide the solutions to the NCERT textbook for Class 9 Maths.  

Q: Where can I find the complete solutions of NCERT textbook for Class 9 Maths ?
A:

Here, students can get detailed NCERT solutions for Class 9 Maths on the links given in this article, or they can check the official website of Careers360. Practising these real numbers class 9 solutions is important as these provide confidence to students, which ultimately leads to a high score.

Q: How does the NCERT solutions are helpful ?
A:

NCERT solutions are helpful for students if they get stuck while solving NCERT problems. Also, these solutions are provided in a very detailed manner, which will give them conceptual clarity.

Q: What are the important topics in NCERT class 9 maths chapter 1 Number Systems?
A:

The basic concepts of the number system, rational numbers, whole numbers, integers, irrational numbers, real numbers, representation of real numbers on the number line, and operations on real numbers are important topics of this chapter.

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