Understanding the Greatest Common Factor (GCF)

The video tutorial explains how to find the greatest common factor (GCF) of 30 and 45 using a factor tree method. It begins with an introduction to the concept of GCF and the use of factor trees. The tutorial then demonstrates creating factor trees for the numbers 30 and 45, identifying their prime factors. A factor chart is used to organize these prime factors and identify common ones. The video concludes by calculating the GCF as 15 and encourages viewers to subscribe for more educational content.

What is the first step in finding the GCF of two numbers using a factor tree?

• Multiply the numbers

• Add the numbers together

• Break down the numbers into their prime factors

• Identify the largest number

Which of the following is a prime factor of 30?

• 9

• 6

• 10

• 3

What is the result of multiplying 3 and 5 in the factor tree of 30?

• 10

• 20

• 8

• 15

Which pair of numbers is used to start the factorization of 45?

• 3 and 15

• 6 and 7

• 2 and 22

• 5 and 9

What is the purpose of creating a factor chart?

• To add the numbers

• To multiply the numbers

• To reduce mistakes by organizing prime factors

• To divide the numbers

What is the rule for finding the GCF using a factor chart?

• Add all the numbers

• Multiply all the numbers

• Divide the largest number by the smallest

• Find pairs of common prime factors

What is the GCF of 30 and 45?

• 10

• 15

• 5

• 20