Roll 3 fair six-sided dice. Let $X_1, X_2, X_3$ be the corresponding numbers.
Calculate $F_{X_1,X_2,X_3}(4, 2, 6)$.
I am confused by this problem. I assumed the answer was $\frac{1}{6}\cdot\frac{1}{6}\cdot\frac{1}{6}$, but this is wrong. The correct answer is $\frac{2}{9}$.