Question 894070
Let a and b be the numbers.


If ab > a + b, then ab - a - b > 0 <--> (a-1)(b-1) > 1.


Let x = a-1, y = b-1. a+b > 4 if and only if x+y > 2. The problem reduces to showing that if xy > 1, then x+y > 2, however this is fairly easy to show.