Solution: The LCM of 47 and 69 is 3243
Methods
How to find the LCM of 47 and 69 using Prime Factorization
One way to find the LCM of 47 and 69 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 47?
What are the Factors of 69?
Here is the prime factorization of 47:
4
7
1
47^1
4 7 1
And this is the prime factorization of 69:
3
1
×
2
3
1
3^1 × 23^1
3 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: 47, 3, 23
3
1
×
2
3
1
×
4
7
1
=
3243
3^1 × 23^1 × 47^1 = 3243
3 1 × 2 3 1 × 4 7 1 = 3243
Through this we see that the LCM of 47 and 69 is 3243.
How to Find the LCM of 47 and 69 by Listing Common Multiples
The first step to this method of finding the Least Common Multiple of 47 and 69 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, 47 and 69:
What are the Multiples of 47?
What are the Multiples of 69?
Let’s take a look at the first 10 multiples for each of these numbers, 47 and 69:
First 10 Multiples of 47: 47, 94, 141, 188, 235, 282, 329, 376, 423, 470
First 10 Multiples of 69: 69, 138, 207, 276, 345, 414, 483, 552, 621, 690
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 47 and 69 are 3243, 6486, 9729. Because 3243 is the smallest, it is the least common multiple.
The LCM of 47 and 69 is 3243.
Find the LCM of Other Number Pairs
Want more practice? Try some of these other LCM problems:
What is the LCM of 37 and 132?
What is the LCM of 74 and 105?
What is the LCM of 144 and 100?
What is the LCM of 129 and 60?
What is the LCM of 48 and 71?