PurposesStudent model building; Reasoning; Representation
DescriptionIn the previous day’s session, students conjectured that, once they had a model for comparing the fractions 2/3 and 3/4, it was possible to build another model twice the size of that original model.
In this session, Alan uses the doubling conjecture to build three models to compare 1/2 and 2/5. The first model uses one orange rod to represent 1; the second uses two orange rods to represent 1; the third model uses four orange rods to represent 1. Alan conjectures that adding four orange rods to his largest model would result in a very large model that will also work.
This analytic is from raw video A73, October 8, 1993.
