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Vikram says: 'For any two rational numbers a and b, a - b = b - a.'
Which single pair of values proves him wrong?

Class 8Operations on Rational NumbersRational Numbers

A $a = \frac{1}{2}, b = \frac{1}{3}$
B $a = \frac{2}{5}, b = \frac{2}{5}$
C $a = \frac{1}{4}, b = \frac{1}{4}$
D $a = 0, b = 0$

Step-by-Step Solution

Take

a = \frac{1}{2}, b = \frac{1}{3} : a - b = \frac{1}{6}

but

b - a = - \frac{1}{6}

. They differ, so subtraction is not commutative.

Answer: A)

a = \frac{1}{2}, b = \frac{1}{3}

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