Factors
Facing Your Fears about Factors
Factors of a number are the numbers that are multiplied to each other to create that larger number.
Factors include:

Prime numbers
Prime numbers are numbers that can only be divided by themselves and 1. They are numbers that can not be created by multiplying any other numbers together.
eg. 2, 3, 5, 7, 11, 13, 17, 19, etc. 
Composite numbers
Composite numbers are all the numbers that are not prime numbers.
Prime Factors
Prime factors are all the prime numbers that can be multipled together to get any composite number. Most people use a factor tree to find these but it is a very confusing method. Instead simply use a downstep method. Always start by dividing with the smallest prime number and work your way up, using all of the prime numbers smaller than the number, if needed. Avoid using the tree method, it is cumbersome and confusing.
eg. What are the prime factors of 56?
(for each step, always start by dividing by the smallest prime number)
 (divide 56 by 2)..................2 56
 (divide 28 by 2)..................2 28
 (divide 14 by 2)..................2 14
 (divide 7 by 7)....................7 7
 (divide 1 by 1)....................1 1
 so the prime factors are 2, 2, 2, 7 (some teachers also count 1, some don't)
Greatest Common Factor
Greatest = largest number
Common = the number they have in common
Factor = multiple
eg. 24 and 18
 24 can be divided by 1, 2, 3, 4, 6, 8, 12
 18 can be divided by 1, 2, 3, 6, 9
The largest (or greatest) factor they have in common is 6.
Greatest Common Factors Lesson
Finally Fascinated by Factors
Teaching Resources for Math for Factoring — teaching and practice worksheets.
Factor Worksheets
Return to Math Skills Index.
Factoring in Success.
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