The least common multiple is the smallest multiple two (or more) numbers have in common. For example, to find the least common multiple of 4 and 6, you’d compare their multiples: Multiples of 4: 4, 8, 12, 16, 20…. Multiples of 6: 6, 12, 18, 24, 30…. The smallest number both 4 and 6 have in common is 12, so 12 is the least common multiple.