Q:

What is the LCM of 28 and 60?

Accepted Solution

A:
Solution: The LCM of 28 and 60 is 420 Methods How to find the LCM of 28 and 60 using Prime Factorization One way to find the LCM of 28 and 60 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 28? What are the Factors of 60? Here is the prime factorization of 28: 2 2 × 7 1 2^2 × 7^1 2 2 × 7 1 And this is the prime factorization of 60: 2 2 × 3 1 × 5 1 2^2 × 3^1 × 5^1 2 2 × 3 1 × 5 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, 7, 3, 5 2 2 × 3 1 × 5 1 × 7 1 = 420 2^2 × 3^1 × 5^1 × 7^1 = 420 2 2 × 3 1 × 5 1 × 7 1 = 420 Through this we see that the LCM of 28 and 60 is 420. How to Find the LCM of 28 and 60 by Listing Common Multiples The first step to this method of finding the Least Common Multiple of 28 and 60 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, 28 and 60: What are the Multiples of 28? What are the Multiples of 60? Let’s take a look at the first 10 multiples for each of these numbers, 28 and 60: First 10 Multiples of 28: 28, 56, 84, 112, 140, 168, 196, 224, 252, 280 First 10 Multiples of 60: 60, 120, 180, 240, 300, 360, 420, 480, 540, 600 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 28 and 60 are 420, 840, 1260. Because 420 is the smallest, it is the least common multiple. The LCM of 28 and 60 is 420. Find the LCM of Other Number Pairs Want more practice? Try some of these other LCM problems: What is the LCM of 98 and 13? What is the LCM of 14 and 53? What is the LCM of 91 and 17? What is the LCM of 71 and 26? What is the LCM of 38 and 143?