Common Factors Study Guide

What are Common Factors?

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.

Finding Common Factors

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.

Example:

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

Using Multiplication to Check

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.

Example:

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.

Study Tips

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.