Sometimes developing a proof is a natural way of thinking through a problem. For example, a teacher posed the problem of finding four consecutive integers whose sum is 44. The students tried the task and decided it was impossible. The teacher responded, "OK, so you couldn't find the integers. How do you know that someone else won't be able to find them?" The students worked quietly for a few minutes, and one student offered, "Look, if you call the first number n, the next three are n + 1, n + 2, and n + 3. Add those four numbers and set them equal to 44. You get 4n + 6 = 44, and the solution to that equation is n = 9 1/2. So no whole number does it." Here the proof works nicely to explain why something is impossible.