Solution: The LCM of 42 and 139 is 5838
Methods
How to find the LCM of 42 and 139 using Prime Factorization
One way to find the LCM of 42 and 139 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 42?
What are the Factors of 139?
Here is the prime factorization of 42:
2
1
×
3
1
×
7
1
2^1 × 3^1 × 7^1
2 1 × 3 1 × 7 1
And this is the prime factorization of 139:
13
9
1
139^1
13 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: 2, 3, 7, 139
2
1
×
3
1
×
7
1
×
13
9
1
=
5838
2^1 × 3^1 × 7^1 × 139^1 = 5838
2 1 × 3 1 × 7 1 × 13 9 1 = 5838
Through this we see that the LCM of 42 and 139 is 5838.
How to Find the LCM of 42 and 139 by Listing Common Multiples
The first step to this method of finding the Least Common Multiple of 42 and 139 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, 42 and 139:
What are the Multiples of 42?
What are the Multiples of 139?
Let’s take a look at the first 10 multiples for each of these numbers, 42 and 139:
First 10 Multiples of 42: 42, 84, 126, 168, 210, 252, 294, 336, 378, 420
First 10 Multiples of 139: 139, 278, 417, 556, 695, 834, 973, 1112, 1251, 1390
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 42 and 139 are 5838, 11676, 17514. Because 5838 is the smallest, it is the least common multiple.
The LCM of 42 and 139 is 5838.
Find the LCM of Other Number Pairs
Want more practice? Try some of these other LCM problems:
What is the LCM of 95 and 90?
What is the LCM of 64 and 23?
What is the LCM of 87 and 93?
What is the LCM of 102 and 150?
What is the LCM of 122 and 32?