Prime Factorization and GCF Concepts

The video tutorial explains how to find the greatest common factor (GCF) of two or three numbers using a factor tree method. It begins with an introduction to the concept of GCF and the factor tree technique. The tutorial then provides three examples: finding the GCF of 18 and 45, 108 and 300, and finally 54, 72, and 90. Each example demonstrates the step-by-step process of creating factor trees and identifying common prime factors. The video concludes with a summary and offers additional practice resources.

What is the greatest common factor (GCF)?

• The sum of two numbers

• The product of two numbers

• The largest number that divides two numbers evenly

• The smallest number that divides two numbers

In the factor tree method, what should you do when you reach a prime number?

• Ignore it

• Circle it

• Divide it by 2

• Multiply it by 2

What is the prime factorization of 18?

• 2 x 3 x 3

• 2 x 2 x 3

• 3 x 3 x 5

• 3 x 5 x 5

Which prime factors do 18 and 45 have in common?

• One 2

• Two 3s

• Two 2s

• One 5

Tags

CCSS.4.OA.B.4

Why is the factor tree method useful for larger numbers?

• It is more accurate

• It is easier to understand

• It requires less calculation

• It is faster than listing all factors

What is the prime factorization of 108?

• 2 x 2 x 3 x 3 x 3

• 2 x 3 x 3 x 5

• 2 x 2 x 2 x 3

• 3 x 3 x 3 x 5

What is the GCF of 108 and 300?

• 15

• 6

• 9

• 12

Which numbers are used to find the GCF of 54, 72, and 90?

• 2 and 3

• 3 and 5

• 2 and 5

• 3 and 4

What is the GCF of 54, 72, and 90?

• 18

• 12

• 30

• 24

What should you do if you want more practice with finding the GCF?

• Try different methods

• Ask a friend for help

• Check the link in the description for a worksheet

• Watch the video again