What is the least common multiple of 9 and 21? (LCM of 9 and 21)?

What is the Least Common Multiple of 9 and 21?

The Least Common Multiple (LCM) of 9 and 21 is the smallest positive number that is a multiple of both 9 and 21.

Here we will show you two different ways to figure out the Least Common Multiple of 9 and 21.

Our favorite way is to find the prime factors of each number and then merge them together to get the answer.

The prime factor(s) of 9 are:
3 x 3

The prime factor(s) of 21 are:
3 x 7

Merging them together using the least amount of factors, you get:

3 x 3 x 7

Then you can multiply those numbers together to get the Least Common Multiple (LCM) of 9 and 21 as follows:

63

To find the Least Common Multiple of 9 and 21, you can also make a list of multiples of 9 and a list of multiples of 21.

Multiples of 9 would be 9, 18, 27, 36 and so on.

Multiples of 21 would be 21, 42, 63, 84 and so on.

Now, compare the two lists to find the smallest number the two lists have in common, which is the Least Common Multiple of 9 and 21. You will once again see that the answer will be:

63

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What is the Least Common Multiple of 9 and 22?
Go here for the next Least Common Multiple on our list that we calculated.

We used used the following sources to solve the problem on this page:

Prime Factorization of 9

Prime Factorization of 21

Multiples of 9

Multiples of 21