Prime Factorization Worksheets with Factor Trees

Strengthen math skills with this collection of free prime factorization worksheets. Students break down numbers into their prime factors using factor trees, a simple visual method for organizing the steps of prime factoring.

These printable worksheets are ideal for reinforcing concepts like prime numbers, prime factors, and factor trees in a clean, easy‑to‑use format, for homework, review, or independent math practice.

A blank factor tree template is also available so you can customize the numbers and create additional practice problems.

An answer key is included with each worksheet, but keep in mind that some numbers can be factored using different intermediate steps. Even if the factor trees look different, they will still lead to the same prime factors.

Worksheet 1 Worksheet 2
Blank Factor Trees Template for Worksheets

If you plan to use the blank template, here are numbers that work well in the first row (numbers with exactly two prime factors). These are “familiar” values found in standard multiplication facts:

4, 6, 9, 10, 14, 15, 21, 22, 25, 33, 35, 49, 55, 77

Here are potential numbers for the second and third rows (numbers with exactly three prime factors). These are also “familiar” and appear within standard multiplication facts:

8, 12, 18, 20, 28, 30, 44, 45, 50, 63, 66, 70, 99

Blank Worksheet Template

For more practice or help with other pre-algebra topics, try our workbooks.

Pre-Algebra Workbook with Explanations, Examples, Practice Problems and Solutions
Mastering Fractions Workbook with Factors and Multiples

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