Solution: The LCM of 81 and 17 is 1377
Methods
How to find the LCM of 81 and 17 using Prime Factorization
One way to find the LCM of 81 and 17 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 81?
What are the Factors of 17?
Here is the prime factorization of 81:
3
4
3^4
3 4
And this is the prime factorization of 17:
1
7
1
17^1
1 7 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: 3, 17
3
4
×
1
7
1
=
1377
3^4 × 17^1 = 1377
3 4 × 1 7 1 = 1377
Through this we see that the LCM of 81 and 17 is 1377.
How to Find the LCM of 81 and 17 by Listing Common Multiples
The first step to this method of finding the Least Common Multiple of 81 and 17 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, 81 and 17:
What are the Multiples of 81?
What are the Multiples of 17?
Let’s take a look at the first 10 multiples for each of these numbers, 81 and 17:
First 10 Multiples of 81: 81, 162, 243, 324, 405, 486, 567, 648, 729, 810
First 10 Multiples of 17: 17, 34, 51, 68, 85, 102, 119, 136, 153, 170
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 81 and 17 are 1377, 2754, 4131. Because 1377 is the smallest, it is the least common multiple.
The LCM of 81 and 17 is 1377.
Find the LCM of Other Number Pairs
Want more practice? Try some of these other LCM problems:
What is the LCM of 134 and 51?
What is the LCM of 44 and 103?
What is the LCM of 5 and 77?
What is the LCM of 13 and 26?
What is the LCM of 11 and 142?