Starting with the 2 dice: which combinations of dice rolls yield 8?
- 2 with dice1, and 6 with dice2
- 6 with dice1, and 2 with dice1
(these are two different events!)
Count them, and count how many different combinations of dice rolls (with two dice) are possible overall.
Before you start with the 3 dice, it helps to look at the probability distribution of 2-dice-rolls, as there's a simple pattern to it.