How do you find the LCM for 4 different numbers?

Answer 1

Write down every number spaced out side by side. Under them, write the multiples of that number; start with the first ten. Try to find the lowest multiple that all numbers have. (Start with the highest number.) If you don't have one, keep adding multiples. (My suggestion is doing them 3 at a time.)

or

The same as with two.
Example: 30, 42, 54, 60
Factor them.
2 x 3 x 5 = 30
2 x 3 x 7 = 42
2 x 3 x 3 x 3 = 54
2 x 2 x 3 x 5 = 60
Combine the factors, eliminating duplicates.
2 x 2 x 3 x 3 x 3 x 5 x 7 = 3780, the LCM