1. **State the problem:** Evaluate the expression $10^{-5}$. 2. **Recall the rule for negative exponents:** For any nonzero number $a$ and integer $n$, $a^{-n} = \frac{1}{a^n}$. 3. **Apply the rule:** $$10^{-5} = \frac{1}{10^5}$$ 4. **Calculate $10^5$:** $$10^5 = 100000$$ 5. **Write the final answer:** $$10^{-5} = \frac{1}{100000} = 0.00001$$ This means $10^{-5}$ is the decimal number 0.00001.