Q:

What is the LCM of 23 and 7?

Accepted Solution

A:
Solution: The LCM of 23 and 7 is 161 Methods How to find the LCM of 23 and 7 using Prime Factorization One way to find the LCM of 23 and 7 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 23? What are the Factors of 7? Here is the prime factorization of 23: 2 3 1 23^1 2 3 1 And this is the prime factorization of 7: 7 1 7^1 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: 23, 7 7 1 × 2 3 1 = 161 7^1 × 23^1 = 161 7 1 × 2 3 1 = 161 Through this we see that the LCM of 23 and 7 is 161. How to Find the LCM of 23 and 7 by Listing Common Multiples The first step to this method of finding the Least Common Multiple of 23 and 7 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, 23 and 7: What are the Multiples of 23? What are the Multiples of 7? Let’s take a look at the first 10 multiples for each of these numbers, 23 and 7: First 10 Multiples of 23: 23, 46, 69, 92, 115, 138, 161, 184, 207, 230 First 10 Multiples of 7: 7, 14, 21, 28, 35, 42, 49, 56, 63, 70 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 23 and 7 are 161, 322, 483. Because 161 is the smallest, it is the least common multiple. The LCM of 23 and 7 is 161. Find the LCM of Other Number Pairs Want more practice? Try some of these other LCM problems: What is the LCM of 15 and 137? What is the LCM of 26 and 146? What is the LCM of 104 and 120? What is the LCM of 55 and 61? What is the LCM of 47 and 128?