Solution: The LCM of 81 and 145 is 11745
Methods
How to find the LCM of 81 and 145 using Prime Factorization
One way to find the LCM of 81 and 145 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 145?
Here is the prime factorization of 81:
3
4
3^4
3 4
And this is the prime factorization of 145:
5
1
×
2
9
1
5^1 × 29^1
5 1 × 2 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: 3, 5, 29
3
4
×
5
1
×
2
9
1
=
11745
3^4 × 5^1 × 29^1 = 11745
3 4 × 5 1 × 2 9 1 = 11745
Through this we see that the LCM of 81 and 145 is 11745.
How to Find the LCM of 81 and 145 by Listing Common Multiples
The first step to this method of finding the Least Common Multiple of 81 and 145 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 145:
What are the Multiples of 81?
What are the Multiples of 145?
Let’s take a look at the first 10 multiples for each of these numbers, 81 and 145:
First 10 Multiples of 81: 81, 162, 243, 324, 405, 486, 567, 648, 729, 810
First 10 Multiples of 145: 145, 290, 435, 580, 725, 870, 1015, 1160, 1305, 1450
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 145 are 11745, 23490, 35235. Because 11745 is the smallest, it is the least common multiple.
The LCM of 81 and 145 is 11745.
Find the LCM of Other Number Pairs
Want more practice? Try some of these other LCM problems:
What is the LCM of 93 and 110?
What is the LCM of 4 and 89?
What is the LCM of 130 and 87?
What is the LCM of 34 and 55?
What is the LCM of 105 and 112?