Question

Which of the following is not true?
(i) Whole numbers are closed under subtraction.
(ii) Integers are not closed under division.
(iii) Rational numbers are closed under division.

• A. (i), (ii), (iii)
• B. (i), (iii)
• C. (i), (ii)
• D. (ii), (iii)

Answer 1

The correct option is B

(i), (iii)

(i) 5 - 9 = -4, which is not a whole number. So whole numbers are not closed under subtraction.
(ii) (-6) ÷ 7, -6 and 7 are integers but -6 ÷ 7 is not an integer. So Integers are not closed under division.
(iii) $\frac{4}{3}$ ÷ 0 is not defined but $\frac{4}{3}$ and 0 are rational numbers. So, rational numbers are not closed under division.