We come across different mathematical operations while dealing with numbers. We say that basic four operations are as follows: Addition, Subtraction, Multiplication and division.
By Addition we mean to find the sum of given two numbers. Now let us look at inverse operation of addition. Subtraction is the inverse operation of Addition, which simply means that if we add two Integers 'a' and 'b', and get the result as “c”, then we also can write above relation in reverse order as follows:

c – a = b and c – b = a,

Thus we come to the conclusion that Subtraction is the inverse operation of Addition. It also indicates that if same number is once added and then same number is subtracted from the given number, then result will remain exactly same.
In the same way we also say that if any of the number is added to its additive inverse, then result we get will be zero. It will be clear by following example:

Let us consider the number +5, so additive inverse of the number 5 will be – 5. Now if we will add original number and its additive inverse we get always zero. It can be written as follows: +5 – 5 = 0.
On the other hand we say that inverse of any of negative number will be a positive number, so if we have a number say -4, then its additive inverse will be – (-4) = 4, which is a positive number.

So we say that zero is the additive identity of any given number. It simply means that if we will add zero to any number, it always results in the same number itself. Mathematically it is represented as follows:

If “a” is any number, then we write:

a + 0 = a.