Question

Divide the sum of 12/5 and 21/25 by their difference

Answer 1

$(\frac{12}{5} + \frac{21}{25} ) \div ( \frac{12}{5} - \frac{21}{25} )$
=(81/25)/(39/25)
=81/39

Answer 2

sum-: 12/5+21/25 = 81/25
difference-: 39/25

now divide 81/25 by 39/25
=81/25÷39/25
cross multiply them (as we do in fraction)