A quick easy game: Monopoly Money Madness
Materials: play money, 2 dice.
Math content: addition, money recognition, unitizing (grouping into new amounts.)
Game play: Very simple – roll two dice, and take that much money. If you can group your money into a larger bill (for example, a five and five ones into a ten dollar bill). First player to $100 wins.
Variation: have players “shop” a catalog or the web for something they would like. Play until they have enough to buy the item they would like.
Money as a context offers some nice practice for developing unitizing, the understanding that allows learners to flexibly exchange between a groups and individual members, or the ability to switch what you are considering as a unit. (I.e. switching from dollars to quarters or cents.) It is such a key concept for 2nd grade, as students move from single digit arithmetic to multidigit arithmetic. Lack of understanding in this will follow them for the rest of elementary school.
From Mathematics in the City: Measuring Teacher Change in Facilitating Mathematizing, Catherine Twomey Fosnot, Maarten Dolk, et al. (link goes to a pdf of the article)
Unitizing requires that children use number to count not only objects, but alsoAs we look at state content expectations, it's pretty clear they are focusing on skills. Fosnot and Dolk (in Math in the City, their books on Young Mathematicians at Work, and their curriculum Contexts for Learning) have a nice way of organizing content into skills, ideas, and models, and then representing them on a landscape. The preservice teachers took their information and tried to do the same for money. Here's what they got: (as a pdf)
groups—and to do them both simultaneously. The whole is thus seen as a group of a
number of objects. The parts together become the new whole, and the parts (the objects in
the group) and the whole (the group) can be considered simultaneously. For learners,
unitizing is a shift in perspective. Children have just learned to count ten objects, one by
one. Unitizing these ten things as one thing—one group, requires almost a negating of the
original idea of number. It is a huge shift in thinking for children, and in fact, was a huge
shift in mathematics, taking centuries to develop. Understanding that a square in a tiled
array can represent a column and a row simultaneously also involves a construction of
part/whole relations (Battista et. al., 1998), as does the relationship between
multiplication and division. There are many more. Because “big ideas” involve
part/whole relations, they require a shift in perspective by learners.