Last week, the price of a movie ticket was $100. This year the price is down by 20%. What's the new price of the movie ticket?
The price of the book is down by: 100*0.2 = $<T>multiply(100, 0.2)=20.0
So the new price of the movie ticket is: 100 - 20 = $<T>subtract(100, 20)=80
