Understanding LCM and GCF through Prime Factorization

This video tutorial by Mumu Math and Science explains how to find the Least Common Multiple (LCM) and Greatest Common Factor (GCF) of multiple numbers using prime factorization. The instructor demonstrates the process with several examples, including factor trees for numbers like 18, 24, 5, 3, 7, and 2. The video emphasizes the importance of identifying and circling prime numbers to simplify the calculation of LCM and GCF. The tutorial provides a step-by-step guide to ensure understanding, making it easier to apply the method to any set of numbers.

What is the primary method suggested for finding the LCM and GCF of more than three numbers?

• Using a calculator

• Prime factorization

• Trial and error

• Graphical method

When creating a factor tree, what should you do with prime numbers?

• Write them in a separate list

• Underline them

• Circle them

• Ignore them

What is the importance of circling prime numbers in factor trees?

• To make them look neat

• To use them in other calculations

• To easily identify them for LCM and GCF calculations

• To separate them from composite numbers

What is the first step in finding the GCF of multiple numbers?

• Identify common prime numbers

• Find the largest number

• Multiply all numbers

• Add all numbers together

How do you determine the LCM when a prime number is found in more than one number?

• Write it multiple times

• Write it once

• Ignore it

• Multiply it by itself

In the example with numbers 5, 3, and 4, what is the GCF?

• 5

• 3

• 2

• 1

What is the LCM of the numbers 5, 3, and 4?

• 60

• 30

• 15

• 45

In the final example, what is the LCM of the numbers given?

• 36

• 54

• 126

• 72

What should you do if a prime number is not found in all numbers when finding the GCF?

• Ignore it

• Consider it as zero

• Multiply it by itself

• Consider the GCF as one

What is the final step in calculating the LCM?

• Add all numbers

• Multiply all identified primes

• Subtract the smallest number

• Divide by the GCF