Q:

What is the LCM of 123 and 140?

Accepted Solution

A:
Solution: The LCM of 123 and 140 is 17220 Methods How to find the LCM of 123 and 140 using Prime Factorization One way to find the LCM of 123 and 140 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 123? What are the Factors of 140? Here is the prime factorization of 123: 3 1 × 4 1 1 3^1 × 41^1 3 1 × 4 1 1 And this is the prime factorization of 140: 2 2 × 5 1 × 7 1 2^2 × 5^1 × 7^1 2 2 × 5 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: 3, 41, 2, 5, 7 2 2 × 3 1 × 5 1 × 7 1 × 4 1 1 = 17220 2^2 × 3^1 × 5^1 × 7^1 × 41^1 = 17220 2 2 × 3 1 × 5 1 × 7 1 × 4 1 1 = 17220 Through this we see that the LCM of 123 and 140 is 17220. How to Find the LCM of 123 and 140 by Listing Common Multiples The first step to this method of finding the Least Common Multiple of 123 and 140 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, 123 and 140: What are the Multiples of 123? What are the Multiples of 140? Let’s take a look at the first 10 multiples for each of these numbers, 123 and 140: First 10 Multiples of 123: 123, 246, 369, 492, 615, 738, 861, 984, 1107, 1230 First 10 Multiples of 140: 140, 280, 420, 560, 700, 840, 980, 1120, 1260, 1400 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 123 and 140 are 17220, 34440, 51660. Because 17220 is the smallest, it is the least common multiple. The LCM of 123 and 140 is 17220. Find the LCM of Other Number Pairs Want more practice? Try some of these other LCM problems: What is the LCM of 61 and 140? What is the LCM of 17 and 147? What is the LCM of 59 and 32? What is the LCM of 26 and 90? What is the LCM of 127 and 141?