Tim gets 6 hours of sleep 2 days in a row.  To make up for it he sleeps 10 hours the next 2 days.  How much sleep did he get?
He got 2*6=<T>multiply(2, 6)=12 hours the first 2 days.
The next 2 days he gets 2*10=<T>multiply(2, 10)=20 hours.
So he got 12+20=<T>add(12, 20)=32 hours.
