Understanding LCM and GCF

The video tutorial from Mumu Math and Science explains how to find the Lowest Common Multiple (LCM) and the Greatest Common Factor (GCF) using prime factorization and factor trees. It begins with an introduction to the concepts of LCM and GCF, followed by a detailed explanation of creating factor trees to simplify numbers into their prime factors. The tutorial then demonstrates how to find the GCF by identifying common prime factors across numbers and how to find the LCM by multiplying the highest power of all prime factors present. An example with four numbers is provided to illustrate the process, and the video concludes with a summary of the methods discussed.

What does LCM stand for?

• Lowest Common Multiple

• Largest Common Multiple

• Lowest Common Measure

• Largest Common Measure

What happens to numbers when you multiply them?

• They disappear

• They get larger

• They stay the same

• They get smaller

What is the purpose of creating a factor tree?

• To divide numbers

• To subtract numbers

• To find prime factors

• To add numbers

Which of the following is a prime number?

• 4

• 6

• 5

• 8

When finding the GCF, what are you looking for?

• A number that is only in one of the numbers

• A number that is in all of the numbers

• A number that is the largest

• A number that is the smallest

What is the rule for using prime factors when calculating the LCM?

• Use each factor three times

• Use each factor only once

• Use each factor twice

• Use each factor as many times as possible

What is the first step in finding the LCM?

• Find prime factors

• Multiply all numbers

• Subtract all numbers

• Add all numbers

In the example with four numbers, what is the LCM?

• 120

• 240

• 840

• 420

What is the GCF of 30, 24, and 14?

• 7

• 3

• 2

• 5

What is the final step in calculating the LCM?

• Add the prime factors

• Multiply the prime factors

• Divide the prime factors

• Subtract the prime factors