A chef needs to make french fries.  He can get 25 fries out of 1 potato.  He has 15 potatoes and he needs 200 fries.  How many potatoes will he have leftover?
To make 200 fries he will need 200 / 25 fries per potato = <T>divide(200, 25)=8.0 potatoes.
He has 15 potatoes - 8 potatoes = <T>subtract(15, 8)=7 leftover potatoes.
