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.

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.

Created on2016-06-28T22:31:25-0400

Published on2016-07-11T10:20:34-0400

Persistent URLhttp://dx.doi.org/doi:10.7282/T3RR21CM