Also, for the Chevalier de Mere and Birthday Problems, knowledge of complementary events is useful. The multiplication rule for independent events is another fundamental result that is of great utility. It could be argued that the site could be used with very little pre-requisites, as a motivation to learn the methods of probability theory. I'd love to hear your experiences with this site, whatever your teaching philosophy. The activities in this website are of two types.
Students make independent choices, and consider alternatives in whole class discussions.
They may change their choices. In addition, the social setting makes the enterprise of comprehension more meaningful. I have therefore deliberately omitted answers. The other type are the Essential Questions . They are more general questions aimed at unifying probabilistic themes across a range of activities and curriculum areas.