John buys 5 toys that each cost $3.  He gets a 20% discount.  How much did he pay for everything?
The toys cost 5*3=$<T>multiply(5, 3)=15
His discount is worth 15*.2=$<T>multiply(15, 0.2)=3.0
So he pays 15-3=$<T>subtract(15, 3)=12
