Uniform probability

What is the probability to win at the lottery? Or to write your name if you choose randomly one by one as many letters as your name needs?

Carlo will explain what is the uniform probability on a finite set, where every single outcome has the same “possibility” to occur: in this case probabilities are an application of combinatorics. We will be able to answer to questions, however we will not cover the wide filed of probabilities (and questions like: what is the probability to have a 6 with a rigged dice?)