Cribbage

Walter taught Maia to play cribbage. In cribbage you score by making totals of 15 with combination of cards, as well as pairs and runs. In addition, three and four of a kind score as 3 and 6 pairs, which is the number of distinct pairs you can make. Similarly, a hand such as 2-3-3-4 scores as two runs (and a pair). So it is an introduction to combinatorics (the mathematics of counting was of combining and ordering things) as well as simple counting and addition.