Q:

What is the LCM of 21 and 53?

Accepted Solution

A:
Solution: The LCM of 21 and 53 is 1113 Methods How to find the LCM of 21 and 53 using Prime Factorization One way to find the LCM of 21 and 53 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 53? 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 53: 5 3 1 53^1 5 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: 3, 7, 53 3 1 × 7 1 × 5 3 1 = 1113 3^1 × 7^1 × 53^1 = 1113 3 1 × 7 1 × 5 3 1 = 1113 Through this we see that the LCM of 21 and 53 is 1113. How to Find the LCM of 21 and 53 by Listing Common Multiples The first step to this method of finding the Least Common Multiple of 21 and 53 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 53: What are the Multiples of 21? What are the Multiples of 53? Let’s take a look at the first 10 multiples for each of these numbers, 21 and 53: First 10 Multiples of 21: 21, 42, 63, 84, 105, 126, 147, 168, 189, 210 First 10 Multiples of 53: 53, 106, 159, 212, 265, 318, 371, 424, 477, 530 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 53 are 1113, 2226, 3339. Because 1113 is the smallest, it is the least common multiple. The LCM of 21 and 53 is 1113. Find the LCM of Other Number Pairs Want more practice? Try some of these other LCM problems: What is the LCM of 133 and 75? What is the LCM of 140 and 51? What is the LCM of 77 and 92? What is the LCM of 90 and 150? What is the LCM of 99 and 3?