1. **Problem statement:** We have two normal six-sided dice, and we want to find the probability that the sum of the two dice is exactly 9. 2. **Formula and rules:** The total number of possible outcomes when rolling two dice is $6 \times 6 = 36$ because each die has 6 faces. The probability of an event is given by: $$\text{Probability} = \frac{\text{Number of favorable outcomes}}{\text{Total number of outcomes}}$$ 3. **Find favorable outcomes:** We need pairs $(d_1, d_2)$ such that $d_1 + d_2 = 9$ where $d_1$ and $d_2$ are integers from 1 to 6. Possible pairs: - $(3,6)$ - $(4,5)$ - $(5,4)$ - $(6,3)$ There are 4 favorable outcomes. 4. **Calculate probability:** $$\text{Probability} = \frac{4}{36}$$ 5. **Simplify fraction:** $$\frac{4}{36} = \frac{\cancel{4}^1}{\cancel{36}^9} = \frac{1}{9}$$ **Final answer:** The probability that the sum of the two dice is exactly 9 is $\boxed{\frac{1}{9}}$.