Jack and Jill are friends who borrow from each other often. Last week Jack borrowed  $1200 from Jill, which he promised to pay back with an interest of 10%. How much will Jack pay back?
The interest on the loan is 0.1*1200=$<T>multiply(0.1, 1200)=120.0
The total amount Jack needs to pay back is 1200+120=<T>add(1200, 120)=1320
