Solution: The LCM of 123 and 17 is 2091
Methods
How to find the LCM of 123 and 17 using Prime Factorization
One way to find the LCM of 123 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 123?
What are the Factors of 17?
Here is the prime factorization of 123:
3
1
×
4
1
1
3^1 × 41^1
3 1 × 4 1 1
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, 41, 17
3
1
×
1
7
1
×
4
1
1
=
2091
3^1 × 17^1 × 41^1 = 2091
3 1 × 1 7 1 × 4 1 1 = 2091
Through this we see that the LCM of 123 and 17 is 2091.
How to Find the LCM of 123 and 17 by Listing Common Multiples
The first step to this method of finding the Least Common Multiple of 123 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, 123 and 17:
What are the Multiples of 123?
What are the Multiples of 17?
Let’s take a look at the first 10 multiples for each of these numbers, 123 and 17:
First 10 Multiples of 123: 123, 246, 369, 492, 615, 738, 861, 984, 1107, 1230
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 123 and 17 are 2091, 4182, 6273. Because 2091 is the smallest, it is the least common multiple.
The LCM of 123 and 17 is 2091.
Find the LCM of Other Number Pairs
Want more practice? Try some of these other LCM problems:
What is the LCM of 29 and 118?
What is the LCM of 142 and 84?
What is the LCM of 35 and 64?
What is the LCM of 128 and 38?
What is the LCM of 42 and 92?