The same breadth of useful interaction extends to the role of the teacher. IPL materials
are meant to permit flexibility in teaching styles. One design goal for IPL is to
provide a method that is consistent with National Council of Teachers of Mathematics
(2000) prescriptions, but that does not hinge on the exceptional skills and
supports necessary to conduct much reform-based instruction. A key move in
achieving this goal is freeing the teacher from the rhetorical task of exerting selective
pressure towards a canonical solution. This can soften the natural inclination
of the teacher to “deliver” during the invention-presentation couplets. It is a precarious
task to lead a classroom of students, often with different ideas in mind, to the
standard solution or to provide just-in-time instruction without “spilling the beans”
and destroying the active process of knowledge evolution. Because the purpose of
these activities is to prepare students to learn, the teacher does not have to guide
classroom discussion and invention towards a conventional solution. It is sufficient
to help students notice properties of distributions and the work that their representations
are trying to accomplish. As we show in the following studies, the pay off
can come later, when the teacher provides direct instruction or resources that offer
the conventional solution invented by experts.