Answer:
The additive identity postulate
Step-by-step explanation:
6 + 0 = 6
Any number added with zero, we get the same number.
That is, a + 0 = a, where "a" is any real number.
Let's take a = 9, we get
9 + 0 = 9
Let's check out a few more examples:
-9 + 0 = -9
2/3 + 0 = 2/3
22 + 0 = 22
You can see any number added with 0, we get the same number.
Here 0 is additive identity, this is called additive identity postulate.
We are given 6 + 0 = 6 which illustrated by "The additive identity postulate."
Therefore, answer is "The additive identity postulate"