Help is NOT a good title for this post. It should be Math, etc.
Sra
Greatest Common Factor of 15 and 21
2 answers
http://www.math.com/school/subject1/lessons/S1U3L2GL.html
http://www.helpwithfractions.com/greatest-common-factor.html
Note that you're looking for the GREATEST common factor, not the LEAST common factor.
http://www.helpwithfractions.com/greatest-common-factor.html
Note that you're looking for the GREATEST common factor, not the LEAST common factor.