Solution: The LCM of 77 and 39 is 3003
Methods
How to find the LCM of 77 and 39 using Prime Factorization
One way to find the LCM of 77 and 39 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 77?
What are the Factors of 39?
Here is the prime factorization of 77:
7
1
×
1
1
1
7^1 × 11^1
7 1 × 1 1 1
And this is the prime factorization of 39:
3
1
×
1
3
1
3^1 × 13^1
3 1 × 1 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, 11, 3, 13
3
1
×
7
1
×
1
1
1
×
1
3
1
=
3003
3^1 × 7^1 × 11^1 × 13^1 = 3003
3 1 × 7 1 × 1 1 1 × 1 3 1 = 3003
Through this we see that the LCM of 77 and 39 is 3003.
How to Find the LCM of 77 and 39 by Listing Common Multiples
The first step to this method of finding the Least Common Multiple of 77 and 39 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, 77 and 39:
What are the Multiples of 77?
What are the Multiples of 39?
Let’s take a look at the first 10 multiples for each of these numbers, 77 and 39:
First 10 Multiples of 77: 77, 154, 231, 308, 385, 462, 539, 616, 693, 770
First 10 Multiples of 39: 39, 78, 117, 156, 195, 234, 273, 312, 351, 390
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 77 and 39 are 3003, 6006, 9009. Because 3003 is the smallest, it is the least common multiple.
The LCM of 77 and 39 is 3003.
Find the LCM of Other Number Pairs
Want more practice? Try some of these other LCM problems:
What is the LCM of 150 and 114?
What is the LCM of 73 and 90?
What is the LCM of 28 and 132?
What is the LCM of 59 and 144?
What is the LCM of 6 and 52?