“Which team will win? - introducing tree diagrams and the method of collecting data which is then interpreted in terms of what we would expect if we could collect enough data
The dog ate my homework - building on this, expressing expected results in the form of proportions, and hence answering questions about how likely an event is
Who is cheating? - from expected results to probabilities in the form of fractions, and the multiplication rule (and onto conditional probability)
Prize Giving - from experiment to sampling with and without replacement…”

http://nrich.maths.org/newprobapproach