### Theory:

Adding the opposite of a number to the same number will equal to $$0$$ (zero).
Inverse property of addition: For every integer ($$a$$) there exists another opposite integer ($$-a$$) such that:

$$a +$$ ($$-a$$) $$= 0$$.
Example:
$$12$$$$+$$($$-12$$)$$=$$$$0$$.

Additive inverse of $$a$$ is $$-a$$.

Important!
• Addition and subtraction are inverse operations of each other.
• Integers doesn't have multiplicative inverses.