Solution: The LCM of 21 and 94 is 1974
Methods
How to find the LCM of 21 and 94 using Prime Factorization
One way to find the LCM of 21 and 94 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 21?
What are the Factors of 94?
Here is the prime factorization of 21:
3
1
×
7
1
3^1 × 7^1
3 1 × 7 1
And this is the prime factorization of 94:
2
1
×
4
7
1
2^1 × 47^1
2 1 × 4 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, 7, 2, 47
2
1
×
3
1
×
7
1
×
4
7
1
=
1974
2^1 × 3^1 × 7^1 × 47^1 = 1974
2 1 × 3 1 × 7 1 × 4 7 1 = 1974
Through this we see that the LCM of 21 and 94 is 1974.
How to Find the LCM of 21 and 94 by Listing Common Multiples
The first step to this method of finding the Least Common Multiple of 21 and 94 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, 21 and 94:
What are the Multiples of 21?
What are the Multiples of 94?
Let’s take a look at the first 10 multiples for each of these numbers, 21 and 94:
First 10 Multiples of 21: 21, 42, 63, 84, 105, 126, 147, 168, 189, 210
First 10 Multiples of 94: 94, 188, 282, 376, 470, 564, 658, 752, 846, 940
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 21 and 94 are 1974, 3948, 5922. Because 1974 is the smallest, it is the least common multiple.
The LCM of 21 and 94 is 1974.
Find the LCM of Other Number Pairs
Want more practice? Try some of these other LCM problems:
What is the LCM of 125 and 39?
What is the LCM of 42 and 136?
What is the LCM of 106 and 61?
What is the LCM of 59 and 7?
What is the LCM of 129 and 89?