Question

What is the additive identity?

Answer 1

a+0 = 0+a = a

Answer 2

Adding onto geerky42's reply (no pun intended), the Additive Identity essentially states that you may add 0 to any value and you will still end up with the same value.

For example, 5 + 0 = 5.
Other examples, 0 + 1 = 1
8 = 8 + 0
0 + 2 = 2 + 0
4 + 0 = 4 + 0
Note how the last two examples end up equaling the same anyways.

Some people go as far as to say that the number 0 itself is the Additive Identity.