What is LCM and how do we find the LCM of given numbers?

LCM or least common multiple of two or more numbers is the smallest positive number that is a multiple of those two or more numbers

Example:

Find the least common multiple of 4 and 10:

The multiples of 4 are: 4, 8, 12, 16, 20, ...

and the multiples of 10 are: 10, 20, ...

The least of these common multiples is 20

So LCM of 4 and 10 is 20.