Answer:
If there are different denominators in a fraction you have to multiply the denominators by their least common factor(lcm).
Example:
2/4 + 5/8=
We can multiply the 4 and the 2 by 2 to get 4/8.
2/4= 4/8
Then, you add normally.
4/8+5/8= 9/8
And remember you cant add the denominator it stays the same, that is why we made them the same.