Quantitative reasoning plays a crucial role in students' and teachers' successful modeling activities. In a semester-long teaching experiment with an undergraduate student, we explore how her conception of a graph plays a role in her ability to quantify and maintain quantitative structures. We characterize here Lydia's conception of a graph as one…

Research continues to illustrate the important role of covariational and quantitative reasoning in the context of function and graphing. The same body of literature has emphasized that students and teachers often construct meanings for function and graphing that do not foreground these reasoning processes. In order to gain deeper insights into…