Common factors are numbers that divide two or more numbers evenly. In other words, they are the numbers that are factors of two or more given numbers.

To find the common factors of two or more numbers, you can list all the factors of each number and then find the numbers that appear in the factor lists of all the given numbers.

Find the common factors of 12 and 18.

Factors of 12: 1, 2, 3, 4, 6, 12

Factors of 18: 1, 2, 3, 6, 9, 18

Common factors: 1, 2, 3, 6

To check if a number is a common factor of two given numbers, you can multiply the number by another factor to see if it equals one of the given numbers. If it does, then it is a common factor.

Is 3 a common factor of 12 and 18?

12 ÷ 3 = 4

18 ÷ 3 = 6

Since both divisions result in whole numbers, 3 is a common factor of 12 and 18.

1. Memorize the multiplication table to quickly identify common factors.

2. Practice finding common factors of different numbers to strengthen your skills.

3. Use the multiplication method to check if a number is a common factor.

.Study GuideCommon Factors Worksheet/Answer key

Common Factors Worksheet/Answer key

Common Factors Worksheet/Answer key

Common Factors Worksheet/Answer keyGreatest Common Factor of numbers not greater than 24 Worksheet/Answer keyMagic Squares Worksheet/Answer keyStar Mathematics Vocabulary/Answer keyCommon Factors

Algebra (NCTM)

Use mathematical models to represent and understand quantitative relationships.

Model problem situations with objects and use representations such as graphs, tables, and equations to draw conclusions.