What does a negative plus a positive equal?

Answer 1

It depends on the numbers you're adding. If, for example, your problem looks like this: -2 + 2, then your answer is 0. But if it looks like this: -1 + 3, your answer is positive 2. If it looks like this: -3 + 1, your answer is negative 2.
It can be just about anything - positive, negative, or zero. Examples:

5 + (-5) = 0

5 + (-3) = 2

-5 + 3 = -2