Solution: The LCM of 23 and 81 is 1863
Methods
How to find the LCM of 23 and 81 using Prime Factorization
One way to find the LCM of 23 and 81 is to start by comparing the prime factorization of each number. To find the prime factorization, you can follow the instructions for each number here:
What are the Factors of 23?
What are the Factors of 81?
Here is the prime factorization of 23:
2
3
1
23^1
2 3 1
And this is the prime factorization of 81:
3
4
3^4
3 4
When you compare the prime factorization of these two numbers, you want to look for the highest power that each prime factor is raised to. In this case, there are these prime factors to consider: 23, 3
3
4
×
2
3
1
=
1863
3^4 × 23^1 = 1863
3 4 × 2 3 1 = 1863
Through this we see that the LCM of 23 and 81 is 1863.
How to Find the LCM of 23 and 81 by Listing Common Multiples
The first step to this method of finding the Least Common Multiple of 23 and 81 is to begin to list a few multiples for each number. If you need a refresher on how to find the multiples of these numbers, you can see the walkthroughs in the links below for each number.
Let’s take a look at the multiples for each of these numbers, 23 and 81:
What are the Multiples of 23?
What are the Multiples of 81?
Let’s take a look at the first 10 multiples for each of these numbers, 23 and 81:
First 10 Multiples of 23: 23, 46, 69, 92, 115, 138, 161, 184, 207, 230
First 10 Multiples of 81: 81, 162, 243, 324, 405, 486, 567, 648, 729, 810
You can continue to list out the multiples of these numbers as long as needed to find a match. Once you do find a match, or several matches, the smallest of these matches would be the Least Common Multiple. For instance, the first matching multiple(s) of 23 and 81 are 1863, 3726, 5589. Because 1863 is the smallest, it is the least common multiple.
The LCM of 23 and 81 is 1863.
Find the LCM of Other Number Pairs
Want more practice? Try some of these other LCM problems:
What is the LCM of 51 and 108?
What is the LCM of 130 and 21?
What is the LCM of 53 and 49?
What is the LCM of 103 and 114?
What is the LCM of 61 and 118?