In this section, we'll learn how to multiply three one-digit numbers together. If one of the numbers is 5, and another is a multiple of two, then the product of those numbers is a multiple of ten, in which case we can do the problem mentally. If one of the numbers is 5 we could multiplyg the other two numbers first, because multiplying by 5 is easy. That is, multiply by 10, then divide by 2. If one of the numbers happens to be 2, we could multiply the other numbers first because we can double a number mentally. If we can't find a way to ease the computation, we'll fall back to the method of partial products.