John decided to buy 10 pins for himself.  They are normally $20 each but they were on sale for 15% off.  How much did he spend on pins?
The sell reduced the price of each pin by 20*.15=$<T>multiply(20, 0.15)=3.0
So he paid 20-3=$<T>subtract(20, 3)=17 per pin
So the total cost was 17*10=$<T>multiply(17, 10)=170
