Can someone help me with this math question pls?

Each number is graded at the zero exponent gave the result number 1. Why?
I show you in the next example.
First you must know that a∧m / a∧n = a∧(m-n)
a/a =1 or a∧1 / a∧1 = a∧(1-1) = a∧0 = 1
Good luck!!!