<s>[INST] The roll of the dice Find the probability of rolling a sum of three or less on two dice.
(Yes, I know this is an "easy" question but I second quess myslef and like second opinions.) 
 [/INST] $$
   \begin{array}{c|cccccc} X+Y & 1 & 2 & 3 & 4 & 5 & 6 \\ \hline \\ 
                             1 & \color\green{2} & \color\green{3} & 4 & 5 & 6 & 7 \\
                             2 & \color\green{3} &  4 & 5 & 6 & 7 & 8 \\ 
                             3 & 4 & 5 & 6 & 7 & 8 & 9 \\
                             \ddots & \vdots & & & &  & \vdots
\end{array}
$$
Since each entry in the above table is equally likely:
$$ \Pr\left(X+Y \leq 3 \right) = \frac{3}{6 \times 6} = \frac{1}{12}$$
</s>