The second law of indices
$$\frac{a^m}{a^n} = a^{m-n}. \left[\frac{a^m}{a^m} = a^{m-m} = a^{0}; \quad also, \quad \frac{a^m}{a^m} = 1. \quad ? \; a^{0}=1.\right].$$
Doesn't this imply that $0^0$ entails dividing by zero?