Solution: The LCM of 90 and 79 is 7110
Methods
How to find the LCM of 90 and 79 using Prime Factorization
One way to find the LCM of 90 and 79 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 90?
What are the Factors of 79?
Here is the prime factorization of 90:
2
1
×
3
2
×
5
1
2^1 × 3^2 × 5^1
2 1 × 3 2 × 5 1
And this is the prime factorization of 79:
7
9
1
79^1
7 9 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, 3, 5, 79
2
1
×
3
2
×
5
1
×
7
9
1
=
7110
2^1 × 3^2 × 5^1 × 79^1 = 7110
2 1 × 3 2 × 5 1 × 7 9 1 = 7110
Through this we see that the LCM of 90 and 79 is 7110.
How to Find the LCM of 90 and 79 by Listing Common Multiples
The first step to this method of finding the Least Common Multiple of 90 and 79 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, 90 and 79:
What are the Multiples of 90?
What are the Multiples of 79?
Let’s take a look at the first 10 multiples for each of these numbers, 90 and 79:
First 10 Multiples of 90: 90, 180, 270, 360, 450, 540, 630, 720, 810, 900
First 10 Multiples of 79: 79, 158, 237, 316, 395, 474, 553, 632, 711, 790
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 90 and 79 are 7110, 14220, 21330. Because 7110 is the smallest, it is the least common multiple.
The LCM of 90 and 79 is 7110.
Find the LCM of Other Number Pairs
Want more practice? Try some of these other LCM problems:
What is the LCM of 60 and 122?
What is the LCM of 142 and 100?
What is the LCM of 66 and 34?
What is the LCM of 42 and 70?
What is the LCM of 126 and 63?