Suppose you had 5 regular dice. What are the odds of rolling a 2, 3, 5, 5, and a random number?
Odds of rolling 2, 3, 5, 5, and one other with 5 regular dice:
Of these possibilities there are
and of the remaining 4 possibilities there are
and of the remaining 3 possibilities there are
So there are
Probability of the desired result