# What is LCM of 4 and 21?

The LCM of 4 and 21 is the least number which is exactly divisible by both 4 and 21. There are 2 methods to find the LCM of 4 and 21 i.e. by prime factorization and using GCF(4, 21).

## Answer: LCM of 4 and 21 is 84

** Explanation: **

The Least Common Multiple (LCM) is the smallest number which is exactly divisible by the given numbers. We can calculate the LCM of 4 and 21 in many ways, the most commonly used methods are listed below.

## Methods to Find LCM of 4 and 21

The methods to compute the LCM of 4 and 21 are explained below.

- By Common Division Method
- By using the GCF

### Method 1: LCM of 4 and 21 by Common Division Method

In this method, we divide 4 and 21 simultaneously with prime numbers and stop it when we don't have a prime number to divide both 4 and 21.

### Method 2: LCM of 4 and 21 using GCF

The LCM Formula is LCM(X, Y) = (X × Y) / GCF(X, Y)

- 4 × 21 = 84
- GCF(4, 21) = 1

Therefore, the LCM of 4 and 21 = LCM(4, 21) = (4 × 21)/GCF(4, 21) = 84/1 = 84

### Therefore, the LCM of 4 and 21 is 84.

**☛ Also Check:**

- LCM of 3, 5, 7 - LCM(3, 5, 7) = 105
- LCM of 4, 12 - LCM(4, 12) = 12
- LCM of 3, 10 - LCM(3, 10) = 30
- LCM of 6, 8, 12 - LCM(6, 8, 12) = 24
- LCM of 4, 6, 9 - LCM(4, 6, 9) = 36
- LCM of 3, 4 - LCM(3, 4) = 12
- LCM of 3, 12 - LCM(3, 12) = 12