Factor them.
2 x 2 x 5 = 20
2 x 2 x 2 x 2 x 3 = 48
Combine the factors, eliminating duplicates.
2 x 2 x 2 x 2 x 3 x 5 = 240, the LCM
The LCM of 48 and 20 is 240.
The LCM of 44, 48, 20 is 2640.
You need at least two numbers to find an LCM.
The LCM is: 240
240
240
LCM(16, 12) = 48.
The LCM is: 336
240
480
The LCM of 20, 48, and 60 is 240.
LCM(20, 48, 64) = 960