Brad wanted to set up a lemonade stand to earn some money.  Every gallon of lemonade would yield 16 glasses.  He figured it would cost him $3.50 to make every gallon of lemonade.  He made 2 gallons to sell and decided he would sell each glass for $1.00  He drank 5 glasses while sitting in his stand.  He sold all but 6 glasses of lemonade.  How much net profit did Brad earn?
He made 2 gallons and each gallon had 16 glasses so 2*16 = <T>multiply(2, 16)=32 glasses
He drank 5 glasses and had 6 left over which means he would not earn money on 5+6 = <T>add(5, 6)=11 glasses
The total revenue would come from 32-11 = <T>subtract(32, 11)=21 glasses
Each gallon cost $3.50 to make so the total cost was 2*3.50 = $<T>multiply(2, 3.5)=7.0
He sold 21 glasses at $1.00 per glass for a total of 1*21 = $<T>multiply(21, 1)=21
When you take his earnings of $21.00 and subtract the cost of $7.00 his total net profit was 21-7 = $<T>subtract(21, 7)=14
