For example, to find the common multiples of 3 and 4, we list their multiples and then find their common multiples. The multiples of 3 are: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, … The multiples of 4 are: 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, … The common multiples of 3 and 4 are: 12, 24, 36, ….