“Can any Fraction be Turned into a Decimal?” A Case Study of a Mathematical Group Discussion

Abstract

This case study examines two days of teacher-led large group discussion in a fifth grade about a mathematical question intended to support student exploration of relationships among fraction and decimal representations and rational numbers. The purpose of the analysis is to illuminate the teacher's work in supporting student thinking through the use of a mathematical question embedded in a position-driven discussion. The focus is an examination of the ways that the emergence of mathematical ideas is partially shaped by complex interactions among the mathematical contents of the question, the inherent properties of the discourse format and participant structure, and the available computational methods. The teacher's work is conceptualized in terms of actions and practices that coordinate these diverse tools, in constant response to students' concurrent use of them.