Mary goes with her 3 children to the circus. Tickets cost $2 for adults and $1 for children. Mary pays with a $20 bill. How much change will she receive?
Mary's ticket costs $2/ticket * 1 ticket = $<T>multiply(2, 1)=2
Mary's children's tickets cost 3 tickets * $1 = $<T>multiply(3, 1)=3
Together the tickets cost $2 + $3 = $<T>add(2, 3)=5
After paying with a 20-dollar bill, Mary will receive $20 - $5 = $<T>subtract(20, 5)=15
