Q:

What is the LCM of 128 and 5?

Accepted Solution

A:
Solution: The LCM of 128 and 5 is 640 Methods How to find the LCM of 128 and 5 using Prime Factorization One way to find the LCM of 128 and 5 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 128? What are the Factors of 5? Here is the prime factorization of 128: 2 7 2^7 2 7 And this is the prime factorization of 5: 5 1 5^1 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, 5 2 7 × 5 1 = 640 2^7 × 5^1 = 640 2 7 × 5 1 = 640 Through this we see that the LCM of 128 and 5 is 640. How to Find the LCM of 128 and 5 by Listing Common Multiples The first step to this method of finding the Least Common Multiple of 128 and 5 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, 128 and 5: What are the Multiples of 128? What are the Multiples of 5? Let’s take a look at the first 10 multiples for each of these numbers, 128 and 5: First 10 Multiples of 128: 128, 256, 384, 512, 640, 768, 896, 1024, 1152, 1280 First 10 Multiples of 5: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50 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 128 and 5 are 640, 1280, 1920. Because 640 is the smallest, it is the least common multiple. The LCM of 128 and 5 is 640. Find the LCM of Other Number Pairs Want more practice? Try some of these other LCM problems: What is the LCM of 80 and 111? What is the LCM of 124 and 8? What is the LCM of 136 and 27? What is the LCM of 64 and 40? What is the LCM of 15 and 120?