Solution: The LCM of 7 and 115 is 805
Methods
How to find the LCM of 7 and 115 using Prime Factorization
One way to find the LCM of 7 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 7?
What are the Factors of 115?
Here is the prime factorization of 7:
7
1
7^1
7 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: 7, 5, 23
5
1
×
7
1
×
2
3
1
=
805
5^1 × 7^1 × 23^1 = 805
5 1 × 7 1 × 2 3 1 = 805
Through this we see that the LCM of 7 and 115 is 805.
How to Find the LCM of 7 and 115 by Listing Common Multiples
The first step to this method of finding the Least Common Multiple of 7 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, 7 and 115:
What are the Multiples of 7?
What are the Multiples of 115?
Let’s take a look at the first 10 multiples for each of these numbers, 7 and 115:
First 10 Multiples of 7: 7, 14, 21, 28, 35, 42, 49, 56, 63, 70
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 7 and 115 are 805, 1610, 2415. Because 805 is the smallest, it is the least common multiple.
The LCM of 7 and 115 is 805.
Find the LCM of Other Number Pairs
Want more practice? Try some of these other LCM problems:
What is the LCM of 35 and 55?
What is the LCM of 130 and 134?
What is the LCM of 72 and 95?
What is the LCM of 42 and 97?
What is the LCM of 47 and 44?