Multiples of 4: 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52, 56, 60, 64, 68, 72, 76, 80, 84, 88, 92, …
Multiples of 7: 7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77, 84, 91, 98, …
Multiples of 21: 21, 42, 63, 84, …
LCM(4, 7, 21) = 84
Multiples of 7: 7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77, 84, 91, 98, …
Multiples of 21: 21, 42, 63, 84, …
LCM(4, 7, 21) = 84