NCERT Exemplar Solutions
Class 7 - Mathematics - Unit 1: Number System - Multiple Choice Questions
Question 6

Question.  6

Which of the following statements is not true?

(a)

When two positive integers are added, we always get a positive integer.

(b)

When two negative integers are added we always get a negative integer.

(c)

When a positive integer and a negative integer is added we always get a negative integer.

(d)

Additive inverse of an integer 2 is (–2) and additive inverse of (–2) is 2.

Detailed Answer with Explanation:

Why option (c) is NOT true

We will check each option with simple examples.

  1. (a) Two positive integers added → positive

    (3 + 5 = 8)

    Both numbers are positive, so the sum is also positive.

  2. (b) Two negative integers added → negative

    ((-2) + (-7) = -(2 + 7))

    (= -9)

    Adding negatives keeps it negative.

  3. (c) A positive + a negative is always negative

    This is not always true. It depends on which number has the bigger size (magnitude).

    Case 1: Positive is bigger → sum is positive

    (7 + (-2) = 5)

    Case 2: Negative is bigger → sum is negative

    (2 + (-7) = -5)

    Case 3: Equal size → sum is zero

    (4 + (-4) = 0)

    So it is not “always negative”.

  4. (d) Additive inverse

    The additive inverse of a number is what you add to get zero.

    (2 + (-2) = 0)

    ((-2) + 2 = 0)

    So the additive inverse of (2) is (-2), and of (-2) is (2).

Correct choice: (c)

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