Prime Factorization and GCF/LCM Concepts

The video tutorial from Moomoomath and Science explains how to find the Lowest Common Multiple (LCM) and Greatest Common Factor (GCF) of the numbers 20, 30, and 15 using a factor tree method. It demonstrates how to break down numbers into their prime factors, organize them in a chart, and apply rules to calculate the LCM and GCF. The LCM is found by multiplying the highest power of all prime factors, while the GCF is determined by identifying common prime factors across all numbers. The video concludes with a summary and encourages viewers to subscribe for more educational content.

What is the purpose of using a factor tree in finding the LCM and GCF?

• To add the numbers

• To identify prime factors

• To simplify the numbers

• To divide the numbers

Which of the following is a prime factor of 20?

• 5

• 6

• 4

• 3

What is the result of 2 times 5 in the factor tree for 20?

• 10

• 15

• 20

• 25

How many times does the number 2 appear in the prime factorization of 30?

• 2

• 0

• 3

• 1

What is the next step after organizing the prime factors into a chart?

• Multiply the numbers

• Add the numbers

• Divide the numbers

• Subtract the numbers

Which rule is used when multiplying numbers for the LCM?

• Use the largest number

• Use all numbers

• Use only one number from each column

• Use the smallest number

What is the LCM of 20, 30, and 15?

• 75

• 60

• 30

• 45

Which number is common in the prime factors of 20, 30, and 15?

• 2

• 5

• 3

• 4

What is the GCF of 20, 30, and 15?

• 2

• 3

• 10

• 5

What should you look for when determining the GCF?

• Numbers that are the smallest

• Numbers that are the largest

• Numbers that are in all lists

• Numbers that are only in one list