Answer:
Numerator: A + 8
Complete Form:

Explanation:
Hello!
If we have two fractions that are being added or subtracted with the same denominator, we can simply add up the numerators and keep it over the same denominator.
Let's use this question as an example:
The problem is basically saying, "If I took A slices from b slices and 8 slices from b slices, how many slices would I have?"
The answer would be A + 8 slices.