Students review the Track Problem by discussing in their small groups. Since students sometimes interpret the straightaway or width of the track differently or incorrectly, it is important that the group agrees on a problem solving approach and answer. I debrief the problem as a whole class by having a student volunteer present his/her thinking, which also gives me the chance to address the idea of attending to precision when considering the number of digits of pi students used when carrying out their work (MP3). After this discussion, I have at least two students read their explanations out loud and give everyone an additional minute or two to make modifications or additions to their own written explanations.
Extreme Couponing: Pizza Edition forces students to grapple with a rather challenging task: determining whether doubling the sector angle or radius of a pizza slice provides a better deal. The coupon image engages students, posing them with a question they want to answer. In the past, some of the best solutions involve students using a compass and straightedge and/or tracing paper to illustrate their ideas (MP5).
We debrief the task by having at least a couple of groups share out their solutions so we can critique each other’s reasoning and make connections (MP3).
NOTE: I found the original coupon image and problem on Dan Meyer’s blog.