Classical probability: This is what we are taught in school, based on the symmetries of coins, dice, packs of cards, and so on, and can be defined as, ‘The ratio of the number of outcomes favouring the event divided by the total number of possible outcomes, assuming the outcomes are all equally likely.’ For example, the probability of throwing a ‘one’ on a balanced die is 1/6, since there are six faces. But this definition is somewhat circular, as we need to have a definition of ‘equally likely’.
