Grades K-8 Worksheets
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Prime factorization means finding all the prime numbers that are factors of a number. A composite number can be written as a product of all of its prime factors.
Example of Prime Factorization
The number 24 can be written as a product of prime numbers
24 = 2 x 2 x 2 x 3
It is called the prime factorization of 24.
Factor Trees
A factor tree shows the prime factors of a composite number in a "tree-like" form. Drawing factor trees is a good way of doing prime factorization.
You can make different factor trees to find the same prime factorization. Look at the two examples below.

and both give the same prime factorization.
Other Examples of Factor Trees

shows 2 x 3 x 5 as the prime factorization of 30. Note: You could get the same result with a different tree!

shows 2 x 2 x 2 x 2 x 2 as the prime factorization of 32.
Prime Factorization Worksheets
- Finding Prime Factorization (1 of 2) (with factor trees)
- Finding Prime Factorization (2 of 2) (with factor trees)