# What is the LCM of 18 and 21?

The Least Common Multiple is also referred to as the Lowest Common Multiple ( **LCM** ) and Least Common Divisor ( LCD) . For two integers a and b, denoted **LCM**(a,b), the **LCM** is the smallest positive integer that is evenly divisible by both a and b.

## Answer: LCM of 18 and 21 is 126

## Explanation:

We can calculate LCM using various methods such as

LCM of 18 and 21 by Listing Method

In this method the first few multiples of 18 and 21 are listed below and the lowest common multiple is chosen

### LCM of 18 and 21 by Formula

The formula of LCM is LCM (a, b) = (a × b) / GCF (a, b)

The Greatest Common Factor of (18, 21) = 3

By substituting we get,

LCM of 18 and 21 = (18 × 21) / 3

= 378/3

= 126

LCM of 18 and 21 = 126