Solution: The LCM of 105 and 71 is 7455
Methods
How to find the LCM of 105 and 71 using Prime Factorization
One way to find the LCM of 105 and 71 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 105?
What are the Factors of 71?
Here is the prime factorization of 105:
3
1
×
5
1
×
7
1
3^1 × 5^1 × 7^1
3 1 × 5 1 × 7 1
And this is the prime factorization of 71:
7
1
1
71^1
7 1 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, 5, 7, 71
3
1
×
5
1
×
7
1
×
7
1
1
=
7455
3^1 × 5^1 × 7^1 × 71^1 = 7455
3 1 × 5 1 × 7 1 × 7 1 1 = 7455
Through this we see that the LCM of 105 and 71 is 7455.
How to Find the LCM of 105 and 71 by Listing Common Multiples
The first step to this method of finding the Least Common Multiple of 105 and 71 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, 105 and 71:
What are the Multiples of 105?
What are the Multiples of 71?
Let’s take a look at the first 10 multiples for each of these numbers, 105 and 71:
First 10 Multiples of 105: 105, 210, 315, 420, 525, 630, 735, 840, 945, 1050
First 10 Multiples of 71: 71, 142, 213, 284, 355, 426, 497, 568, 639, 710
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 105 and 71 are 7455, 14910, 22365. Because 7455 is the smallest, it is the least common multiple.
The LCM of 105 and 71 is 7455.
Find the LCM of Other Number Pairs
Want more practice? Try some of these other LCM problems:
What is the LCM of 108 and 121?
What is the LCM of 92 and 137?
What is the LCM of 141 and 75?
What is the LCM of 106 and 51?
What is the LCM of 128 and 147?