40, 80 & 120.
15 & 20 have an infinite number of Common Multiples; the first three are 60, 120 and 180.
10, 20, 30 The common multiples of 5 and 10 are multiples of their lowest common multiple. The lcm of 5 and 10, is 10. Thus the first three common multiples are 10, 20, 30.
1, 660, 5580
20, 40, 60
20, 40, and 60.
10, 20, 30
10, 20, 30
140, 280, 420
140, 280, 420
They are: 180, 360 and 540
20, 40, 60.
20, 40 and 60