If Katherine has 4 apples and 3 times as many pears in her fridge, how many bananas does she have if she has a total of 21 pieces of fruit?
Katherine has a total of 3 * 4 apples = <T>multiply(3, 4)=12 pears
She therefore had 4 apples + 12 pears = <T>add(4, 12)=16 apples and pears
We know she has 21 total pieces of fruit, so this means she must have 21 total - 16 = <T>subtract(21, 16)=5 bananas
