Tom starts with 50 balls. Amy starts with 28 balls. If Tom gives 22 balls to Amy, what percentage of balls does Tom have compared with Amy?

This question requires 2 logical steps. The first is to calculate how many balls Tom and Amy have after the transaction. The second is to use a formula to calculate the percentage of balls left . Reading the question carefully is always crucial in problem solving questions to figure out which maths function will be used for each person. In this case, Tom is giving to Amy, so Tom is going to lose 22 balls (-) and Amy will gain 22 (+). This give us Tom with 50-22=28 and Amy will have 28+22=50.Once this is established, the student must recall how to work out a percentage of a number compared to another number. For this example, the formula used is (A/B)*100. Reading the question reveals that we want to know Tom's percentage of Amy's ball. Substituting in the final values gives (28/50)100=56%. If the brackets aren't in the right place the student might end up with 28/(50100) which would give an incorrect answer of 0.0056%.