When a number is negative,it's opposite is also it's?

When a number is negative,it's opposite is also it's    Additive Inverse.

For example -2, it's opposite is = +2

And +2 is the additive inverse of -2, because -2 + (+2) = -2 + 2 = 0

And if both numbers add up to 0, they are additive inverse of each other.

The second option

Step-by-step explanation:

all the angles of a triangle add up to 180