CBSE Class 9 Maths Worksheet Chapter 1 Number System

1. It is impossible to represent a rational number in decimal form.

1. Terminating

2. Non- terminating

3. Repeating or Non- Terminating

4. Non-repeating or Non- terminating

2. Between two rational numbers

1. There is no rational number.

2. There is exactly one rational number.

3. There are infinitely many rational numbers.

4. There are only rational numbers and no irrational numbers.

3. The product of any two irrational numbers,

1. is always an irrational number.

2. is always a rational number.

3. is always an integer.

4. can be rational or irrational.

4. Which of the following is irrational?

1. $\sqrt{7}$

2. $\sqrt{81}$

3. $\dfrac{\sqrt{12}}{\sqrt{3}}$

4. $\dfrac{\sqrt{4}}{9}$

5. What is the value is $\sqrt{4} \times \sqrt{81}$?

1. 36

2. 18

3. 16

4. 42

6. Fill in the blanks;

1. Any two integers are separated by a finite number of others …..

2. There are an ….. amount of rational numbers between 15 and 18.

3. X+Y is a rational number if x and y are both ……

4. Value of $\sqrt[3]{8}$ …….

7. Match the Column:

8. Using two irrational numbers as an example:

1. Product is an irrational number.

2. Difference is an irrational number.

3. Division is an irrational number.

9. Simplify; $(\sqrt{5}+\sqrt{6})(\sqrt{5}-\sqrt{6})$.

10. Simplify; $\sqrt[3]{1331}-\sqrt{100}+\sqrt{81}$.

11. Calculate the value of $\dfrac{11^{\dfrac{1}{2}}}{11^{\dfrac{1}{4}}}$.

12. Calculate the $\dfrac{x}{y}$ form of $0.777 . . . . .$, where $\mathbf{x}$ and $\mathbf{y}$ are integers and $\mathbf{y}$ does not equal to zero.

13. Find three rational number between $\dfrac{9}{11}$ and $\dfrac{5}{11}$.

14. The value of $\dfrac{\sqrt{8}+\sqrt{12}}{\sqrt{32}+\sqrt{48}}$.

15. The value of $a^b+b^a$, if $\mathbf{a}=2$ and $\mathbf{b}=3$

16. Simplify; $2^{\dfrac{2}{3}} \cdot 2^{\dfrac{1}{5}}$

17. Find the value of $\dfrac{1}{a^b+b^a}$, where $a=5, \mathbf{b}=2$

18. Arrange in ascending order $\sqrt[3]{2}, \sqrt{3}, \sqrt[6]{5} \text {. }$

19. Simplify $(4 \sqrt{5}+3 \sqrt{7})^2$

20. Find the value of a, If $\left(\dfrac{y}{x}\right)^{2a-8}=\left(\dfrac{x}{y}\right)^{a-1}$.

21. Rationalize the denominators of $\dfrac{1}{\sqrt{7}}$.

22. Recall, $\pi$ is defined as the ratio of circumference (say c) 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?

23. Express $0 . \overline{001}$ in the form of $\dfrac{p}{q}$, where $\mathrm{p}$ and $\mathrm{q}$ are integers and $\mathrm{q} \neq 0$.

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

25. Find six rational numbers between 3 and 4.

Answers to the Worksheet:

1. (d)

A rational number cannot have a non-terminating or non-repeating decimal form.

2. (c) 

Between two rational numbers, there are infinitely many rational numbers. 

E.g. $\dfrac{3}{5}$ and $\dfrac{4}{5}$ are two rational numbers, then $\dfrac{31}{50} \dfrac{32}{50} \dfrac{33}{50} \dfrac{34}{50} \dfrac{35}{50} \ldots$ are infinite rational number between them.

3. (d) 

The product of two irrational numbers can be rational or irrational depending on the two numbers.

For example, $\sqrt{3} \times \sqrt{3}$ is 3 which is a rational number whereas $\sqrt{2} \times \sqrt{4}$ is $\sqrt{8}$ which is an irrational number. As $\sqrt{3}, \sqrt{2}, \sqrt{4}$ are irrational.

Hence, option D is correct.

4. (a) $\sqrt{7}$ is an irrational number.

5. (b) 

$\sqrt{4} \times \sqrt{81}$ $= \sqrt{2^2} \times \sqrt{9^2}$ $= 2 \times 9$ = 18

6. Fill in the blanks.

1. Any two integers are separated by a finite number of other integers.

2. There are an endless amount of rational numbers between 15 and 18 .

3. $\mathrm{X}+\mathrm{Y}$ is a rational number if $\mathrm{x}$ and $\mathrm{y}$ are both rational numbers.

4. Value of $\sqrt[3]{8}$ is $\underline{2}$

7. Match The Column:

Explanation:

8. Given an example of two irrational numbers whose;

1. Product is an irrational number $\sqrt{6} \times \sqrt{3}=\sqrt{6 \times 3}=\sqrt{18}=3 \sqrt{2}$

2. Difference is a irrational number $\sqrt{6}-\sqrt{3}$ = $\sqrt{3}$

3. Division is an irrational number $\dfrac{\sqrt{6}}{\sqrt{3}}=\sqrt{\dfrac{6}{3}}=\sqrt{2}$

9. Simplify; $(\sqrt{5}+\sqrt{6})(\sqrt{5}-\sqrt{6})$ 

We know that, $(a+b)(a-b)=a^2-b^2$

Then,

= $\left((\sqrt{5})^2-(\sqrt{6})^2\right)$

= $5-6$

= $-1$

10. $\sqrt[3]{1331}-\sqrt{100}+\sqrt{81}$

= $\sqrt[3]{11^3}-\sqrt{10^2}+\sqrt{9^2}$

= $11-10+9$

= $1+9$

= 10

11. $\dfrac{11^{\dfrac{1}{2}}}{11^{\dfrac{1}{4}}}$

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

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

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

12. Let, 

$p= 0.777…$ ....   (1)

Multiply both side in above equation 10

Then, 

$10p= 7.777…$ ….(2)

Subtracting equation (1) from (2), we get;

$10p-p= 7.777… - 0.777…$

$9p= 7$

$p= \dfrac{7}{9}$

13. Three rational number between $\dfrac{9}{11}$ and $\dfrac{5}{11}$

Rational number of $\dfrac{9}{11}$ and $\dfrac{5}{11}$ is denominator same

Then,

$= \dfrac{9}{11}, \dfrac{8}{11}, \dfrac{7}{11}, \dfrac{6}{11}, \dfrac{5}{11}$

14. $\dfrac{\sqrt{8}+\sqrt{12}}{\sqrt{32}+\sqrt{48}}$

$= \dfrac{\sqrt{2^3}+\sqrt{4 \times 3}}{\sqrt{8 \times 4}+\sqrt{8 \times 6}}$

$= \dfrac{2 \sqrt{2}+2 \sqrt{3}}{4 \sqrt{2}+4 \sqrt{3}}$

$= \dfrac{2(\sqrt{2}+\sqrt{3})}{4(\sqrt{2}+\sqrt{3})}$

$= \dfrac{(\sqrt{2}+\sqrt{3})}{2(\sqrt{2}+\sqrt{3})}$

$= \dfrac{1}{2}$

15. If $a=2$ and $b=3$

The value of $a^b+b^a$

$= 2^3+3^2$

$= 8+9$

$= 17$

16. $2^{\dfrac{2}{3}} \cdot 2^{\dfrac{1}{5}}$

$2^{\dfrac{2}{3}} \cdot 2^{\dfrac{1}{5}}=2^{\dfrac{2}{3}+\dfrac{1}{5}} \quad \because a^p \cdot a^q=a^{p+q}$

$=2^{\dfrac{10+3}{15}}$

$=2^{\dfrac{13}{15}}$

17. Value of $\dfrac{1}{a^b+b^a}$, where $a=5, b=2$

$= \dfrac{1}{5^2+2^5}$

$= \dfrac{1}{25+32}$

$= \dfrac{1}{57}$

18. Here we have : $\sqrt[3]{2}, \sqrt{3}, \sqrt[5]{5}$

We can also write the expression in simpler form as follows:

$2^{\dfrac{1}{3}}, 3^{\dfrac{1}{2}}, 5^{\dfrac{1}{6}}$

Now we can see that in the denominators of the exponents we have: $3,2,6$

We will now take the LCM of $3,2,6$, which is 6 .

Now we will make all the denominators equal to 6 , so we have to multiply by the multiples in both numerator and denominator.

We can write the numbers as:

$2^{\dfrac{1}{3}} \times \dfrac{2}{2}=2^{\dfrac{2}{6}}$

For the second number we can write:

$3 \dfrac{1}{2} \times \dfrac{3}{3}=3 \dfrac{3}{6}$

Since in the third number we already have the desired denominator, so the third number is

$5^{\dfrac{1}{6}}$

Now we will again write the numbers in the root under, but we have to keep in mind that the numerator will turn as the exponential powers inside the root.

So we have the numbers as:

$\sqrt[6]{2^2}, \sqrt[5]{3^3}, \sqrt[5]{5}$

We will simplify the values inside the root, so we have:

$\sqrt[5]{4}, \sqrt[6]{27}, \sqrt[5]{5}$

From this we can write the smaller value in the front and then the larger value:

$\sqrt[5]{4}, \sqrt[6]{5}, \sqrt[5]{27}$

Hence the original numbers in ascending form are:

$\sqrt[3]{2}, \sqrt[6]{5}, \sqrt{3}$

19. $(4 \sqrt{5}+3 \sqrt{7})^2$

We know that,

$(a+b)^2=a^2+b^2+2 a b$

$=(4 \sqrt{5})^2+(3 \sqrt{7})^2+2 \times (4 \sqrt{5}) (3 \sqrt{7})$

$=80+63+24 \sqrt{5 \times 7}$

$=143+24 \sqrt{35}$

20. $\left(\dfrac{y}{x}\right)^{2 a-8}=\left(\dfrac{x}{y}\right)^{a-1}$

Rewrite,

$\left(\dfrac{y}{x}\right)^{2 a-8}=\left(\dfrac{x}{y}\right)^{8-2 a}$   $ \because (x)^{-a}=\dfrac{1}{x^a}$

Then,

$\left(\dfrac{x}{y}\right)^{8-2 a}=\left(\dfrac{x}{y}\right)^{a-1}$

When the bases of both sides of an equation are the same, then their exponents are also equal.

$\Rightarrow 8-2 a=a-1$

$\Rightarrow 2 a+a=8+1$

$\Rightarrow 3 a=9$

$\Rightarrow a=\dfrac{9}{3}$

$\Rightarrow a=3$

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

(Dividing and multiplying by $\sqrt{7}$ )

$=\dfrac{\sqrt{7}}{7}$

22. Writing $\pi$ as $\dfrac{22}{7}$ is only an approximate value and so we can't conclude that it is in the form of a rational. In fact, the value of $\pi$ is calculating as non-terminating, non-recurring decimal as $\pi=3.14159$ Whereas

If we calculate the value of $\dfrac{22}{7}$ it gives $3.142857$ and hence $\pi \neq \dfrac{22}{7}$

In conclusion $\pi$ is an irrational number.

23. Let $x=0.001001 \ldots \ldots$ (1)

Since 3 digits are repeated multiply both the sides of (1) by 1000

$1000 x=1.001001 \ldots$

$1000 x=1+0.001001 \ldots$

$1000 x=1+x$

$1000 x-x=1$

$999 x=1$

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

$\therefore 0 . \overline{001}=\dfrac{1}{999}$

24. Since we make the denominator the same first, then

$\dfrac{3}{4}=\dfrac{3 \times 5}{4 \times 5}=\dfrac{15}{20}$

$\dfrac{4}{5}=\dfrac{4 \times 4}{5 \times 4}=\dfrac{16}{20}$

Now we need to find 5 rational no.

$\dfrac{15}{20}  =\dfrac{15 \times 6}{20 \times 6}=\dfrac{90}{120}$

$\dfrac{16}{20}=\dfrac{16 \times 6}{20 \times 6}=\dfrac{96}{120}$

$\therefore$ Five rational numbers between $\dfrac{3}{4}$ and $\dfrac{4}{5}$ are $\dfrac{91}{120}, \dfrac{92}{120}, \dfrac{93}{120}, \dfrac{94}{120}$ and $\dfrac{95}{120}$

25. We can find any number of rational numbers between two rational numbers. First of all, we make the denominators same by multiplying or dividing the given rational numbers by a suitable number. If denominator is already same then depending on number of rational no. we need to find in question, we add one and multiply the result by numerator and denominator.

$3=\dfrac{3 \times 7}{7} \text { and } \quad 4=\dfrac{4 \times 7}{7}$

$3=\dfrac{21}{7} \quad \text { and } \quad 4=\dfrac{28}{7}$

We can choose 6 rational numbers as: $\dfrac{22}{7}, \dfrac{23}{7}, \dfrac{24}{7}, \dfrac{25}{7}, \dfrac{26}{7}$ and $\dfrac{27}{7}$

Benefits of Learning Number System in Class 9 Chapter 1 Maths Worksheet The Class 9 Maths Chapter 1 worksheet pdf contains more than enough material to help students better understand what number systems are and how to solve them. The worksheets come with extensive questions, attempting to clear any doubts the students might have about the number system and their types.

The Maths assignment for Class 9 Number System list of questions and answers provide thorough insights on the topic’s resources and offers easy tricks to identify quicker ways to solve the questions faster while also being more aware and making sure students don’t go wrong or commit any silly mistakes in their solutions.

All of these worksheets have been developed by the best mathematicians and experienced arithmetic representatives who are very aware of the needs and requirements of the students of Class 9.

Examples of Usage of Number System for Class 9

These are a few examples of Maths assignments for Class 9 Number System exercises’ examples :

1. Answer the following.

• Find two irrational numbers and two rational numbers between 0.7 and 0.77.

• Every integer is not a whole number. True or false?

• Find at least 7 rational numbers between 2 and 9.

• Write down 4567 in the decimal and binary number systems.

• Is 0 a rational number? State your reasons based on your answer.

Interesting Facts About Number System for Class 9

• There are nine types of number systems in mathematics. They are :

• Natural numbers

• Whole numbers

• Integers

• Fractions

• Rational numbers

• Irrational numbers

• Real numbers

• Imaginary numbers

• Prime and composite numbers

• Natural numbers are the root forms of numbers between 0 to infinity. They are also named “positive numbers” or “counting numbers” and are represented by the symbol N. (1, 2, 3, 4, 5 and so on)

• Whole numbers are natural numbers, with the only difference being the inclusion of 0. They are represented by the symbol W. (0, 1, 2, 3, 4, 5 and so on)

• Integers contain whole numbers and the negative values of natural numbers and don’t include fractions, so their numbers can’t be written in the “a/b” format. It ranges from infinity at the negative end to infinity at the positive end, including 0 and is represented by Z. (...-3, -2, -1, 0, 1, 2, 3… and so on)

• Fractions are numbers written in the “a/b” format, where “a” (numerator) is a whole number, and “b” (denominator) is a natural number. Hence, the denominator can never be 0. (2/4, 0/10, 5/7, etc.)

• Rational numbers can be written in fractions where “a” and “b” are both integers and b ≠ 0. All fractions are rational numbers, but all rational numbers are not fractions.(-5/9, 3/9, -8/14, etc)

• Irrational numbers are numbers that can’t be written in fractional forms. (√8, √.127, √3.209, etc)

• Real numbers can be written in decimals, including whole numbers, integers, fractions, etc. All integers belong to real numbers, but not all real numbers belong to integers. (1.25, 0.467, 8.9, etc.)

• Imaginary numbers are not real numbers, resulting in negative numbers when squared or put together. They are also named complex numbers and are represented by the symbol i. (√-3, √-16, √-1, etc.)

• Numbers that don’t have other factors except 1 are called prime numbers, and the rest of the numbers - except 0 - are called composite numbers, as 0 is neither a prime nor a composite number. ( 2, 3, 5… are prime numbers whereas 4, 6, 8… are composite numbers)

• Other definitions and elaborated explanations will be provided in the operations on real numbers class 9 worksheet pdf and more.

Important Topics for Class 9 Number System

The important topics students will have to learn in the number system syllabus for Class 9 are as follows :

• What are number systems, and how to solve them?

• What are the four types of number systems?

• How to convert one number system to another number system.

• Solving the problems and choosing the correct answer.

• Various other exercises in the Number System Class 9 worksheet

What does the PDF Consist of?

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• It only means that the students must learn by themselves, with the teachers guiding and aiding them throughout their learning process.

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• The worksheet for Class 9 Maths Chapter 1 with Solutions pdfs is free for download at Vedantu’s website.

• Rest assured, all the worksheets adhere to the CBSE guidelines' strict, updated, and revised rules.

Many other Number Systems Class 9 worksheet pdfs are present at Vedantu’s platform, created by their own arithmetic subject matter experts, ensuring that the students receive the best training and exercises needed to test their skills and excel in their examinations.