Factor them.
5 x 5 = 25
2 x 2 x 2 x 5 = 40
Combine the factors, eliminating duplicates.
2 x 2 x 2 x 5 x 5 = 200, the LCM
The LCM is: 200
The LCM of 20, 40, 25 is 200.
The LCM is 600.
The LCM is 200
The LCM is 1800.
The LCM is 1400.
The LCM is: 200
200
600
It is: 600
It is 200
200.