Solution: The LCM of 61 and 115 is 7015
Methods
How to find the LCM of 61 and 115 using Prime Factorization
One way to find the LCM of 61 and 115 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 61?
What are the Factors of 115?
Here is the prime factorization of 61:
6
1
1
61^1
6 1 1
And this is the prime factorization of 115:
5
1
×
2
3
1
5^1 × 23^1
5 1 × 2 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: 61, 5, 23
5
1
×
2
3
1
×
6
1
1
=
7015
5^1 × 23^1 × 61^1 = 7015
5 1 × 2 3 1 × 6 1 1 = 7015
Through this we see that the LCM of 61 and 115 is 7015.
How to Find the LCM of 61 and 115 by Listing Common Multiples
The first step to this method of finding the Least Common Multiple of 61 and 115 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, 61 and 115:
What are the Multiples of 61?
What are the Multiples of 115?
Let’s take a look at the first 10 multiples for each of these numbers, 61 and 115:
First 10 Multiples of 61: 61, 122, 183, 244, 305, 366, 427, 488, 549, 610
First 10 Multiples of 115: 115, 230, 345, 460, 575, 690, 805, 920, 1035, 1150
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 61 and 115 are 7015, 14030, 21045. Because 7015 is the smallest, it is the least common multiple.
The LCM of 61 and 115 is 7015.
Find the LCM of Other Number Pairs
Want more practice? Try some of these other LCM problems:
What is the LCM of 34 and 80?
What is the LCM of 54 and 35?
What is the LCM of 106 and 144?
What is the LCM of 33 and 139?
What is the LCM of 26 and 91?