84, 168, 252
1 and 2 are common factors. 84 and 168 are common multiples.
2,2,7,2
The Least Common Multiple (LCM) for 10 12 14 is 420.
Any multiple of 84
420 is the LCM
14, 28, 42
14, 28, 42.
14, 28, 42.
The lowest common multiple is 84
If that's 9, 14 and 21, the first three common multiples are 126, 252 and 378.
There are many common multiples, but there is only one least common multiple. The LCM is 336, because 336 is the smallest number that is a multiple of all the other three.