![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/step1.JPG\")
Method 1:
\List the factors of each number.
\Factors of 18: 2, 3, 6, 9, 18
\Factors of 28: 2, 4, 7, 14, 28
\Identify the greatest common factor.
\The greatest common factor of 18 and 28 is 2.
\![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/step2.JPG\")
Method 2:
\Write the prime factorization of each number.
\18 = 2 × 3 × 3.
\28 = 2 × 2 × 7.
\The GCF is the product of the common prime factors in each number.
\GCF = 2.
\The greatest common factor of 18 and 28 is 2.
\![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/solution.JPG\")
The greatest common factor of 18 and 28 is 2.