Quandaries
and Queries 

My name is Ken and I am taking my GED course for my High School and have not been in a class for 35 years. I am doing this for retraining. I am at the part about fractions. Here is an example that I am having trouble with. 1 3/7 + 4 2/3 + 11/21 They have no common denominators. Could you PLEASE help me. If you could send me a step by step explanation it would be greatly appreciated. 

Hi Ken, 1 = ^{7}/_{7} so you can write 1 ^{3}/_{7} as ^{10}/_{7}. Also 4 = ^{12}/_{3}and hence 4 ^{2}/_{3} can be written ^{14}/_{3}. Hence the problem becomes
21 = 3 7 and hence 21 is a common denominator. For the first fraction multiply the numerator and denominator by 3 and in the second fraction multiply the numerator and denominator by 7. This gives
Penny


