Solution: The LCM of 20 and 117 is 2340
Methods
How to find the LCM of 20 and 117 using Prime Factorization
One way to find the LCM of 20 and 117 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 20?
What are the Factors of 117?
Here is the prime factorization of 20:
2
2
×
5
1
2^2 × 5^1
2 2 × 5 1
And this is the prime factorization of 117:
3
2
×
1
3
1
3^2 × 13^1
3 2 × 1 3 1
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: 2, 5, 3, 13
2
2
×
3
2
×
5
1
×
1
3
1
=
2340
2^2 × 3^2 × 5^1 × 13^1 = 2340
2 2 × 3 2 × 5 1 × 1 3 1 = 2340
Through this we see that the LCM of 20 and 117 is 2340.
How to Find the LCM of 20 and 117 by Listing Common Multiples
The first step to this method of finding the Least Common Multiple of 20 and 117 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, 20 and 117:
What are the Multiples of 20?
What are the Multiples of 117?
Let’s take a look at the first 10 multiples for each of these numbers, 20 and 117:
First 10 Multiples of 20: 20, 40, 60, 80, 100, 120, 140, 160, 180, 200
First 10 Multiples of 117: 117, 234, 351, 468, 585, 702, 819, 936, 1053, 1170
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 20 and 117 are 2340, 4680, 7020. Because 2340 is the smallest, it is the least common multiple.
The LCM of 20 and 117 is 2340.
Find the LCM of Other Number Pairs
Want more practice? Try some of these other LCM problems:
What is the LCM of 24 and 111?
What is the LCM of 115 and 6?
What is the LCM of 135 and 150?
What is the LCM of 45 and 79?
What is the LCM of 103 and 72?