Factor them.
2 x 2 = 4
2 x 7 = 14
2 x 3 x 5 = 30
Combine the factors, eliminating duplicates.
2 x 2 x 3 x 5 x 7 = 420, the LCM
The LCM of 4 and 30 is 60.
The LCM is: 4,158
The LCM is 140.
The LCM is 196.
The LCM is 420.
The LCM is 140.
The LCM is 56.
LCM(4, 21, 14) = 84
For 14, 8, 7, 4 the LCM is: 56
The Least Common Multiple (LCM) for 12 30 4 is 60.
The LCM is 280.
The LCM is 168.