LCM of 21 and 24

We use LCM of 21 and 24 to find  the smallest number that divides both the numbers equally.  The smallest positive number is the number that divides both numbers equally, is 168 without leaving any remainder. LCM is used mainly in fractions to find a common number for both the integers.
 

The LCM of 21 and 24 can be found by the following methods like division method, listing multiples, prime factorization.
 

In division method, we divide both the numbers, we begin with dividing side by side the smallest number. We continue dividing until we get a common number that divides both the numbers equally. It makes it easier for the children to focus on prime factors and identify them.

• 2 divides 24 and not 21

• 3 divides 24 and 21

• 12 divides 24 and not 21

• 7 divides 21 and not 24.

Now multiply the divisors : 2×3×4×7=168 which is the LCM.
 

Step 1: Start by listing multiples of both the numbers separately:

Multiples of 21 are 21,42,63,84,105,126,147,168…..

Multiples of 24 are 24,48,72,96120,144,168…..

Step 2: The least common factor from the list is 168. Therefore, the LCM of 24 and 21 is 168.

We part both the numbers unto factors:

Factor of 24: 2³×3

Factors of 21: 3×7

Take the powers of both the numbers and multiply together:

LCM=2³x3x7=168.
 

• Prime Factor: A natural number or whole number which has factors that are 1 and itself. For Example, 3 is a prime number.

• Prime Factorization: The process of breaking down a number into its prime factors is called Prime Factorization. For example, the factorization of 14 is 2×7.

• Co-prime numbers: numbers which has the only positive divisor of them both as 1. For example, 6 and 7.