John visits three different countries.  He stays in the first country for 2 weeks and he spends twice as long in each of the other two countries.  How much time does he spend on the trip?
He spends 2*2=<T>multiply(2, 2)=4 weeks in the other two countries
So he spends 2*4=<T>multiply(2, 4)=8 weeks in those countries combined
That means he is gone for 2+8=<T>add(2, 8)=10 weeks
