Question

whats a good and easy way to find the lcm?

Answer 1

List the prime factorization of each number first.
Example: Find the lcm of 75 and 180.
375 = 3 * 5 * 5 * 5
180 = 2 * 2 * 3 * 3 * 5
Next write down each prime number the maximum number of times that it appears with either number, and multiply.
2 * 2 * 3 * 3 * 5 * 5 * 5 = 4500
So the lcm for 375 and 180 is 4500.

Answer 2

Another method if you only have two numbers, not three or more, is to multiply the numbers and divide by the gcf.
(375 * 180)/15 = 4500