# What is the LCM of 20 and 70?

To find the LCM of 20 and 70, we need the least number which is exactly divisible by both 20 and 70.

## Answer: LCM of 20 and 70 is 140

The Least Common Multiple (LCM) of two numbers a and b is the smallest number which is divisible by a and b.

We will use the following methods to find the LCM of 20 and 70.

- LCM of 20 and 70 by Listing Method
- LCM of 20 and 70 by Formula

## Explanation:

We can find the LCM of the numbers in the following two ways.

### Method 1: LCM of 20 and 70 by Listing Method

We will list the first few multiples of 20 and 70 and determine the common multiples.

The least among the common multiples is the LCM (20, 70).

Here, 140 is the least common multiple of 20 and 70.

So, LCM (20, 70) = 140

### Method 2: LCM of 20 and 70 by Formula

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

The Greatest Common Factor (GCF) of 20 and 70 is 10. So, GCF (20, 70) = 10

So, the LCM of 20 and 70 by using the formula,

LCM (20, 70) = (20 × 70) / 10

= 1400 / 10

= 140

LCM of 20 and 70 = 140

Clearly, the solution to our question LCM of 20 and 70 is the same in both methods.