Solution: The LCM of 80 and 100 is 400
Methods
How to find the LCM of 80 and 100 using Prime Factorization
One way to find the LCM of 80 and 100 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 80?
What are the Factors of 100?
Here is the prime factorization of 80:
2
4
×
5
1
2^4 × 5^1
2 4 × 5 1
And this is the prime factorization of 100:
2
2
×
5
2
2^2 × 5^2
2 2 × 5 2
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
2
4
×
5
2
=
400
2^4 × 5^2 = 400
2 4 × 5 2 = 400
Through this we see that the LCM of 80 and 100 is 400.
How to Find the LCM of 80 and 100 by Listing Common Multiples
The first step to this method of finding the Least Common Multiple of 80 and 100 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, 80 and 100:
What are the Multiples of 80?
What are the Multiples of 100?
Let’s take a look at the first 10 multiples for each of these numbers, 80 and 100:
First 10 Multiples of 80: 80, 160, 240, 320, 400, 480, 560, 640, 720, 800
First 10 Multiples of 100: 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000
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 80 and 100 are 400, 800, 1200. Because 400 is the smallest, it is the least common multiple.
The LCM of 80 and 100 is 400.
Find the LCM of Other Number Pairs
Want more practice? Try some of these other LCM problems:
What is the LCM of 24 and 20?
What is the LCM of 109 and 42?
What is the LCM of 115 and 39?
What is the LCM of 65 and 11?
What is the LCM of 50 and 102?