How many favourable outcomes are there when rolling five six-sided dice?

What is the theoretical probability of rolling all the same number on the five dice?

You have not defined what a favorable outcome is for the first question.

The probability of rolling a five of a kind is:

P = (1/6) ^5

P=1/7776

If you have five dice you just have to count up all possible outcomes for each dice. Which means you would have about 30 different possible outcomes.

The possibility of all five landing on the same number is very uncertain considering one dice had a 1/6 chance of landing on a certain number.