MKT and curriculum materials are only part of the story: Insights from a lesson on fractions

This paper investigates the contribution of mathematical knowledge for teaching (MKT) and curriculum materials to the mathematical quality of instruction by comparing the enactment of a fractions problem taught by two teachers with differing MKT. It was found that MKT seem to support teachers' precise use of mathematical language and to prevent errors; the curriculum materials provided a rich representational context for mathematical work....