After many years of teaching mathematics, I still fall into the trap of assuming that my students think as I do. Indeed, this failure to recognize my own assumptions and to acknowledge that others may not share them is at the root of most of my teaching problems.
Rob Wieman, email@example.com, is a doctoral student at the University of Delaware in Newark. He taught for many years in New York City public high schools and is interested in efforts to improve high school mathematics teaching. Sarah Ryan