Purpose: A growing trend in instructional improvement efforts is the use of formative assessment informed by research-based developmental trajectories of how students gain deeper understanding of subject matter content over time. This article reports the findings of a large-scale experimental study of an innovative mathematics professional…

In this article, I analyze episodes from two third-grade classrooms drawn from a larger classroom teaching experiment to explore how these students began to incorporate nonnumerical symbols in their mathematical expressions when asked to represent indeterminate quantities. The article addresses two research questions: What understandings did these…

This project was designed to test Mayer's multimedia theory in an elementary school to improve students' mathematics learning for low-income children. The study designed and developed two multimedia mathematics experiments in 3rd grade: 9's multiplication experiment and geometric solids experiment. The two experimental lessons were implemented in…