So one way to think about it is how many different outcomes are there if we choose four numbers out of 60? Now, this is equivalent to saying how many combinations are there if we have 60 items? In this case, we have 60 numbers, and we are going to choose four. And we don't care about the order. That's why we're dealing with combinations, not permutations. We don't care about the order. How many different groups of four can we pick out of 60?