Solution: The LCM of 68 and 55 is 3740
Methods
How to find the LCM of 68 and 55 using Prime Factorization
One way to find the LCM of 68 and 55 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 68?
What are the Factors of 55?
Here is the prime factorization of 68:
2
2
×
1
7
1
2^2 × 17^1
2 2 × 1 7 1
And this is the prime factorization of 55:
5
1
×
1
1
1
5^1 × 11^1
5 1 × 1 1 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, 17, 5, 11
2
2
×
5
1
×
1
1
1
×
1
7
1
=
3740
2^2 × 5^1 × 11^1 × 17^1 = 3740
2 2 × 5 1 × 1 1 1 × 1 7 1 = 3740
Through this we see that the LCM of 68 and 55 is 3740.
How to Find the LCM of 68 and 55 by Listing Common Multiples
The first step to this method of finding the Least Common Multiple of 68 and 55 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, 68 and 55:
What are the Multiples of 68?
What are the Multiples of 55?
Let’s take a look at the first 10 multiples for each of these numbers, 68 and 55:
First 10 Multiples of 68: 68, 136, 204, 272, 340, 408, 476, 544, 612, 680
First 10 Multiples of 55: 55, 110, 165, 220, 275, 330, 385, 440, 495, 550
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 68 and 55 are 3740, 7480, 11220. Because 3740 is the smallest, it is the least common multiple.
The LCM of 68 and 55 is 3740.
Find the LCM of Other Number Pairs
Want more practice? Try some of these other LCM problems:
What is the LCM of 64 and 19?
What is the LCM of 86 and 87?
What is the LCM of 10 and 24?
What is the LCM of 50 and 124?
What is the LCM of 89 and 66?