In four years, Annika will be three times as old as Hans. If Hans is now 8 years old, how old is Annika now?
In four years, Hans will be 8+4=<T>add(8, 4)=12 years old.
Then Annika will be 12*3=<T>multiply(12, 3)=36 years old.
So Annika right now is 36-4=<T>subtract(36, 4)=32 years old.
