Tom decides to buy some shirts from his favorite fandoms because there is a sale on his favorite website.  He buys 5 t-shirts from each of his 4 favorite fandoms.  The shirts normally cost $15 each but there is a 20% off sale.   The order qualified for free shipping but he still needed to pay 10% tax.  How much did he pay?
He bought 5*4=<T>multiply(5, 4)=20 shirts
The discount saves him 15*.2=$<T>multiply(15, 0.2)=3.0 per shirt
So each shirt cost 15-3=$<T>subtract(15, 3)=12
So the total order cost 20*12=$<T>multiply(20, 12)=240
Tax added 240*.1=$<T>multiply(240, 0.1)=24.0
So he paid 240+24=$<T>add(240, 24)=264
