Johnny is buying planks of wood to build some tables. Each table needs a plank of wood for each of the legs and 5 planks of wood for the surface. If Johnny wants to build 5 tables, how many planks of wood does he need?
Each table needs 1 plank of wood * 4 legs = <T>multiply(1, 4)=4 planks of wood for the legs.
This means each table needs 4 planks of wood for legs + 5 planks of wood for the surface = <T>add(4, 5)=9 planks of wood.
To build 5 tables, Johnny will therefore need 9 planks of wood * 5 tables = <T>multiply(9, 5)=45 planks of wood.
