I begin the investigation of practice, introduce my school, my students, and my classroom, and frame the questions that have guided my inquiry with a description of a bit of my teaching. In this teaching, I used students’ work on a problem to direct their studies of important mathematical skills and ideas. There is nothing particularly special about the lesson I describe here—I could have started anywhere.

In the room where I teach, the desks and chairs are usually arranged in groups of four or six, making “tables” at which students face one another. As the students sit in

EP - 28 PB - Yale University Press PY - 2001 SN - 9780300089738 SP - 9 T2 - Teaching Problems and the Problems of Teaching UR - www.jstor.org/stable/j.ctt32bpsx.5 Y2 - 2020/07/08/ ER -