Finding the Greatest Common Factor (GCF) Pack
Students use the "Upside Down Birthday Cake" method when finding the GCF!

Each year my 5th grade students always confused Least Common Multiple and Greatest Common Factor. In an effort to help them keep the two straight, I try to make the way I present one very different from the way I present the other.

For GCF, I use what I call 'The Upside Down Birthday Cake'. Using a layered cake turned upside down as a visual greatly helps my students distinguish between GCF and LCM. I created this pack to introduce the method to my students. This pack INCLUDES the Greatest Common Factor Poster, which is listed separately in my shop. If you buy this, there is no need to purchase the poster.

The pack includes:

• A GCF matchbook fold-up.

• A poster showing the step-by-step process of how the method works.

• A half sheet copy of the poster, for a student resource and a two page worksheet.

To learn how to print a poster, visit my Making Posters blog post.

When assembling the matchbook fold-up, run a two-sided copy--the front cover (upside down intentionally for easier copying) and the inside. With the inside facing you, bring the top of the paper down to the bottom horizontal line and fold. Then bring the bottom of the paper up and fold on the bottom horizontal line. The result will look like a giant matchbook :)
Save for later
  • FindingtheGreatestCommonFactorGCFPack.pdf

About this resource


Created: Aug 30, 2015

Updated: Feb 22, 2018


pdf, 3 MB


Report a problem

Categories & Grades