NCERT Exemplar Solutions
Class 7 - Mathematics - Unit 1: Number System - Multiple Choice Questions
Question 24

Question.  24

If \(a\) and \(b\) are two integers, then which of the following may not be an integer?

(a)

\(a+b\)

(b)

\(a-b\)

(c)

\(a\times b\)

(d)

\(a\div b\)

Detailed Answer with Explanation:

Step 1: Know what integers are. Integers are whole numbers … like −3, −2, −1, 0, 1, 2, 3, …

Step 2: Check each option one by one.

(a) a + b → Adding two integers always gives an integer.

(2 + 3 = 5)

(-4 + 1 = -3)

(b) a − b → Subtracting two integers always gives an integer.

(5 - 2 = 3)

(-3 - 4 = -7)

(c) a imes b → Multiplying two integers always gives an integer.

(3 imes (-2) = -6)

(d) a div b → Division is not always an integer.

Example where it is not an integer:

(a = 1,; b = 2)

(a div b = 1 div 2 = frac{1}{2})

( frac{1}{2}) is not an integer.

Example where it is an integer (only when (b) divides (a)):

(a = 6,; b = 3)

(a div b = 6 div 3 = 2)

Important: Division by zero is not defined.

(a div 0) → not defined

Conclusion: (a), (b), and (c) are always integers, but (d) may or may not be an integer. So the correct answer is (d).

NCERT Exemplar Solutions Class 7 – Mathematics – Unit 1: Number System – Multiple Choice Questions | Detailed Answers