One of the many changes we’re making to our curriculum is thinking about how to represent negative numbers. We’ve used CPM‘s Algebra Tiles a lot, but this is the first year that we’ll really explore negative tiles, but also the idea of opposite.
Side note: last time we taught this unit, we used the Interactive Math Program’s hot and cold cubes (hot cubes cause an increase, cold cubes cause a decrease). Which I think was a neat idea, except that CPM’s negative tiles are red, which confused students when we talked about hot cubes causing an increase. This was not helped by a school-wide evacuation in the middle of one of our lessons. We had planned a summative project entitled “Mystery Soup” (how many hot and cold cubes are there? Maybe?) but with all the confusion and our eventual movement away from hot and cold cubes, we all seem to have forgotten what “Mystery Soup” refers to.
At any rate, watching the kiddos think about and represent negatives and opposites has been interesting. This group thought of different ways to show an expression with negatives using tiles. Any time we can get kiddos to talk together, but show their own way of thinking is pretty cool: