Question

How to find common denominators

Answer 1

Ok, It's hard to explain so I'll use an example. 
1/5  +   2/15
now you try to find a number that goes into both for this example it would be 3
3*5=15      and then that equals the 2/15
so you then multiply 3 by the numerator getting the fraction
3/15 + 2/15
with the answer of 
5/15 which can be reduced to
1/3