Question

What does subtracting a negative do ?

Answer 1

Do?  I'd answer by saying that subtracting a negative quantity is equivalent to adding the magnitude of that quantity.  For example, 2 - (-3)  = 2 + 3  = 5.

A negative sign in front of another actually calls up addition.

Answer 2

If you subtract negative from negative the answer will be positive if u subtract a nevagative from a positive it will become a negative.