Factor them.
2 x 2 x 2 x 3 x 7 = 168
3 x 5 x 5 x 7 = 525
Combine the factors, eliminating duplicates.
2 x 2 x 2 x 3 x 5 x 5 x 7 = 4200, the LCM
The LCM is 525.
28 is a factor of 168 {28 x 6 = 168}, so the LCM is 168
The LCM is: 168
The LCM is: 168
The LCM is 168.
The LCM is 168.
The LCM is: 525
The LCM is: 168
LCM of 84 and 24 is 168.
The LCM is: 168
168 is the LCM of 24 and 28
The LCM is 840.