Quandaries
and Queries 

Beth How do you use the Greatest Common Factor in addtion and subtraction of fraction? Student in the 7th Grade. 

Hi Beth, It's in the simplification. Suppose that you are to add ^{1}/_{4} and ^{5}/_{12}
Now you need to write ^{8}/_{12} in lowest terms.To do this you need the Greatest Common Factor of 8 and 12. 4 is the Greatest Common Factor of 8 and 12 so you can divide both 8 and 12 by 4 to get
This will not simplify any further since 4 is the greatest factor that is common to 8 and 12. Penny 

