Class 9 Maths MCQs for Chapter 3 The World of Numbers With Answers PDF

MCQs for Class 9 Maths Chapter 3: The World of Numbers are available in this article with a free PDF for offline practice. These MCQs help students revise the important ideas from the chapter in an exam-friendly format. The questions, along with answers and detailed solutions, cover counting numbers, natural numbers, whole numbers, integers, rational and irrational numbers, and number patterns. Regular practice can improve accuracy, clear concepts, and build confidence for exams.

MCQs Questions for Class 9 Maths Chapter 3 The World of Numbers

Question 1: Which of the following is a natural number?

Options:

(A). -2
(B). 0
(C). 9
(D). 3/4

Answer: (C). 9

Explanation: Natural numbers are positive counting numbers starting from 1.

Question 2: Which number is irrational?

Options:

(A). 7/8
(B). 0.5
(C). √3
(D). 12

Answer: (C). √3

Explanation: √3 cannot be written in p/q form.

Question 3: The decimal expansion of 1/4 is:

Options:

(A). 0.25
(B). 0.45
(C). 0.75
(D). 0.5

Answer: (A). 0.25

Explanation: 1 divided by 4 equals 0.25.

Question 4: Which of the following is a whole number?

Options:

(A). -5
(B). 2/3
(C). 0
(D). √7

Answer: (C). 0

Explanation: Whole numbers include 0 and positive integers.

Question 5: What is the square root of 144?

Options:

(A). 10
(B). 11
(C). 12
(D). 13

Answer: (C). 12

Explanation: 12 × 12 = 144.

Question 6: Which number is neither prime nor composite?

Options:

(A). 1
(B). 2
(C). 5
(D). 9

Answer: (A). 1

Explanation: The number 1 has only one factor.

Question 7: The reciprocal of 3/5 is:

Options:

(A). 3/5
(B). 5/3
(C). −5/3
(D). 1

Answer: (B). 5/3

Explanation: The reciprocal is found by interchanging numerator and denominator.

Question 8: Which of the following is a rational number?

Options:

(A). π
(B). √11
(C). 9/13
(D). √15

Answer: (C). 9/13

Explanation: Rational numbers can be expressed in p/q form.

Question 9: Find the value of (− 6) + 14.

Options:

(A). 6
(B). 7
(C). 8
(D). 9

Answer: (C). 8

Explanation: − 6 + 14 = 8.

Question 10: Which number is divisible by both 2 and 5?

Options:

(A). 25
(B). 30
(C). 33
(D). 47

Answer: (B). 30

Explanation: 30 is divisible by both 2 and 5.

Question 11: Which of the following is a perfect square?

Options:

(A). 18
(B). 36
(C). 50
(D). 72

Answer: (B). 36

Explanation: 36 = 6².

Question 12: The decimal expansion of an irrational number is:

Options:

(A). Terminating
(B). Repeating
(C). Non-terminating and non-repeating
(D). Whole number

Answer: (C). Non-terminating and non-repeating

Explanation: Irrational numbers continue endlessly without repetition.

Question 13: What is the cube root of 64?

Options:

(A). 2
(B). 3
(C). 4
(D). 5

Answer: (C). 4

Explanation: 4 × 4 × 4 = 64.

Question 14: Which of the following is an integer?

Options:

(A). 4/7
(B). −12
(C). √8
(D). 5.5

Answer: (B). − 12

Explanation: Integers include negative numbers, zero, and positive numbers.

Question 15: Which of the following is a prime number?

Options:

(A). 15
(B). 21
(C). 29
(D). 35

Answer: (C). 29

Explanation: 29 has only two factors.

Question 16: The HCF of 16 and 24 is:

Options:

(A). 2
(B). 4
(C). 6
(D). 8

Answer: (D). 8

Explanation: 8 is the highest common factor of 16 and 24.

Question 17: Which fraction is already in simplest form?

Options:

(A). 4/12
(B). 6/18
(C). 5/9
(D). 8/20

Answer: (C). 5/9

Explanation: 5 and 9 have no common factor except 1.

Question 18: The additive identity is:

Options:

(A). 0
(B). 1
(C). − 1
(D). 5

Answer: (A). 0

Explanation: Adding 0 does not change the value of a number.

Question 19: What is the square root of 225?

Options:

(A). 13
(B). 14
(C). 15
(D). 16

Answer: (C). 15

Explanation: 15 × 15 = 225.

Question 20: Which of the following is an even number?

Options:

(A). 19
(B). 27
(C). 44
(D). 53

Answer: (C). 44

Explanation: Even numbers are divisible by 2.

Question 21: Which decimal is terminating?

Options:

(A). 2/3
(B). 5/6
(C). 9/20
(D). 7/9

Answer: (C). 9/20

Explanation: 9 ÷ 20 = 0.45.

Question 22: The product of two integers is always:

Options:

(A). Irrational
(B). Rational
(C). Prime
(D). Decimal only

Answer: (B). Rational

Explanation: The product of integers is always rational.

Question 23: Which number is not divisible by 3?

Options:

(A). 24
(B). 39
(C). 44
(D). 57

Answer: (C). 44

Explanation: 44 is not exactly divisible by 3.

Question 24: Which of the following is a composite number?

Options:

(A). 13
(B). 17
(C). 19
(D). 25

Answer: (D). 25

Explanation: 25 has more than two factors.

Question 25: The multiplicative identity is:

Options:

(A). 0
(B). 1
(C). -1
(D). 100

Answer: (B). 1

Explanation: Any number multiplied by 1 remains unchanged.

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