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Mathematics Magazine for Grades 1-12  

 

Greatest Common Factor
 

 

  

The greatest common factor, or GCF, is the greatest factor that divides two numbers. To find the GCF of two numbers:

  1. List the prime factors of each number.

  2. Multiply those factors both numbers have in common. If there are no common prime factors, the GCF is 1.

Ex: prime factor of 12: 2 x 2 x 3 Prime Factor of 18: 2 x 3 x 3
There is one 2 and one 3 in common. 
The Greatest Common Factor (GCF) is 2 x 3 = 6

Find the Greatest Common Factor (GCF) of a group of two or three numbers.

First Number: Second Number: Third Number:
If you only want to do two numbers, leave the Third Box empty.

is the Greatest Common Factor (GCF)

  
 
 

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