google "greatest common factor" and "lowest common denominator"
I'm sure if you know what they are, then you'll be able to answer parts a) and b).
Given the GCF or LCM, what else do you know about each pair of numbers?
a) Two numbers have GCF of 2.
b) Two numbers have an LCM of 2.
Please and thankyou!
2 answers
Here are two excellent sites for learning about GCF and LCM.
http://www.mathsisfun.com/greatest-common-factor.html
http://www.math.com/school/subject1/lessons/S1U3L3GL.html
http://www.mathsisfun.com/greatest-common-factor.html
http://www.math.com/school/subject1/lessons/S1U3L3GL.html