Prime Factorization Worksheets - Factor Trees and Ladder Method Activities

Teaching prime factorization? Make decomposing numbers fun and easy with factor trees and the ladder method. Then your math students will be able to express a whole number as a product of its prime factors.

Open the preview to take a closer look at the activities.

To decompose a number with a factor tree, kids continuously find factor pairs until all are prime. The first page of six worksheets provides directions and an example.

With the ladder method, they continuously divide by prime numbers until they get to one. Again, the first page of six worksheets provides directions and an example.

Why teach prime factorization?

• It gives kids deeper conceptual understanding of multiplication, division, and relationships between numbers.
• Understanding how each whole number decomposes to a set of primes provides a foundation for number theory and prepares kids for higher math.
• At this age, for example, kids need it to handle fractions. (1) To write a fraction in lowest terms, students will better understand how to continually cancel and/or find the greatest common factor (GCF). (2) To add or subtract unlike fractions, they’ll grasp concepts necessary to find the least common multiple (LCM).

Files include everything you need to teach prime factorization in fourth, fifth, or sixth grade:

• Factor tree and ladder method reference guides to use as instructional tools, anchor charts, or handouts
• Divisibility rules poster (and parallel “Is It Prime?” handout for students)
• 6 factor tree worksheets
• 6 ladder method worksheets
• Answers

Resources can be used in a variety of ways.

• Whole class instruction or practice
• Test prep
• Small group work, remediation, or tutoring
• Homework
• Sub plans

Your students will love it – and so will you!

• Decomposing numbers in a repetitive, pictorial way provides helpful strategies – and is satisfying to young mathematicians.
• Your students will have deeper understanding of multiplication, division, and relationships between whole numbers.
• Activities address the intent of your standards. For example, these activities extend CCSS 4.OA.B.4, which asks kids to find factor pairs and determine if a number is prime or composite. Furthermore, it provides background concepts for CCSS 6.NS.B.4.

Listen to what another educator says about these resources.

• “Children I tutor do well grasping concepts when there is a simple graphic to explain the concept. This is a great resource.” – Joy B.

Printable and digital versions of each worksheet are included.

• A PDF provides a traditional pencil and paper option.
• Easel Activities offer digital versions.

You can scaffold learning with related resources.

• Begin with exploration of arrays.
• Then work with a set of factor cards and worksheets.
• When kids are ready, move on to prime factorization with this resource.
• Finally, provide plenty of practice. With number of the day worksheets, students gain confidence and move steadily toward mastery.
• Want it all? Grab the factors and multiples bundle, which includes all of these resources at a discounted price.

Enjoy teaching factor trees and the ladder method!

Brenda Kovich

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I’m committed to continual improvement. This resource was updated on June 3, 2022.