# Prime Factors Worksheets

What Are Prime Factors? The numbers we multiply to get another number are known as the factors. For example, when we multiply 3 and 5, we get 15 (3 x 5 =15). That means that 3 and 5 are the factors of 15. Most numbers have more than one set of factors. Different pairs of numbers, when multiplied, give us the same answer. For instance, 12 can have factors of 3 x 4, 6 x 2, and 1 x 12. However, we have numbers that can only be factored by 1 or by itself. These factors are known as prime factors. These include 2,3, 5,7,11, and 13. Number 1 is usually not regarded as the prime factor as it goes into everything. Often you are required to find out the prime factorization of a number wonâ€™t include 1 but have every copy of the prime factor. If we have to do prime factorization of 8, it would be 2x2x2 and not only 2. Although 2 is the only factor, we need three 2s to make an 8. So, the prime factorization of number 8 would include all three copies of 2.

• ### Basic Lesson

Demonstrates how to find the prime factors of a number. Also includes practice problems.

• ### Intermediate Lesson

Uses a larger more difficult numbers than the basic lesson.

• ### Independent Practice 1

Find all the prime factors of each number. The answers can be found below.

• ### Independent Practice 2

20 practice problems that review prime factors. The answers can be found below.

• ### Homework Worksheet

12 problems to reinforce the lessons and practice pages. An example is provided.

• ### Skill Quiz

10 problems that test prime factoring skills.

• ### Homework and Quiz Answer Key

Answers for the homework and quiz.

• ### Lesson and Practice Answer Key

Answers for both lessons and both practice sheets.

#### No Remainders

A factor is a whole number that divides exactly into a larger number without leaving a remainder. To factor a number, identify all of its prime factors by breaking the number down into its factors until all of the factors are prime.