Divide $7^3$ by $7^6$ and write the answer as a fraction.

Quotient rule: $7^3÷7^6=7^{3-6}=7^{-3}=\frac{1}{7^3}=\frac{1}{343}$. Adding the exponents instead of subtracting them is the classic error here. Dropping the minus sign gives 343, and using $7^4=2401$ is one power too many.