What does the LCM stand for?

Answer 1

LCM = Lowest Common Multiple.

This is the smallest number that is common amongst the multiples of two of more other numbers.

For example:

The multiples of 3 are: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48, ...

The multiples of 5 are: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, ...

The common multiples of 3 and 5 are: 15, 30, 45, ...

The lowest common multiple of 3 and 5 is the smallest of these, namely 15.

An example of its use is for adding fractions as using the lowest common multiple of all the denominators ensures the numbers do not get too big (and cumbersome)