dilemma with a math teacher

Question

A boy spends 1/4 of his money on sweets and 1/3 on computer games. What fraction of his money does he not spend?

Answer 1

You've got to get the two fractions to have the same denominator so you can tell what you have left.

For the sweets, (1/4) is (3/12).

For the games, (1/3) is (4/12).

Add together and you've used up 7/12, so 5/12 remains from what you started with.