Mark is looking to buy a total of 12 pieces of fruit at the store. He has already chosen 3 apples. He has also selected a bunch of bananas containing 4 bananas. How many oranges does he need to pick out to have 12 total pieces of fruit?
He has 3 apples and 4 bananas, so he has 3 + 4 = <T>add(3, 4)=7 pieces of fruit.
He needs to buy 12 fruit - 7 fruit = <T>subtract(12, 7)=5 oranges.
