1. **State the problem:** Simplify the expression $0.15 \times 10^{-2}$ and write the answer in scientific notation. 2. **Recall the scientific notation format:** A number in scientific notation is written as $a \times 10^n$ where $1 \leq |a| < 10$ and $n$ is an integer. 3. **Convert 0.15 to scientific notation:** $$0.15 = 1.5 \times 10^{-1}$$ 4. **Rewrite the original expression using this:** $$0.15 \times 10^{-2} = (1.5 \times 10^{-1}) \times 10^{-2}$$ 5. **Use the property of exponents:** $$a \times 10^m \times 10^n = a \times 10^{m+n}$$ 6. **Apply the exponent addition:** $$1.5 \times 10^{-1 + (-2)} = 1.5 \times 10^{-3}$$ 7. **Final answer:** The simplified expression in scientific notation is $$\boxed{1.5 \times 10^{-3}}$$