p⁰=1 because it is basically saying and when simplifying fractional exponents we can flip the bottom exponent up to the top if we change the sign, leaving us with : (p⁵-p⁵)=p⁰. This helps us because we also know that when we have a fraction that is the same on the top and the bottom: for example, it can simplify down to one. This means that p⁰=1.