Digital tools such as Dynamic Geometry Environment (DGE) have increasingly become prominent in teaching and learning process of mathematics.However, research on DGE involving in-service teachers' teacher professional knowledge is underexplored.Existing studies have concentrated on student learning or teacher collaboration.This paper characterizes the professional knowledge that emerges as in-service mathematics teachers engage with tasks in a DGE during an online, facilitated, simulated professional development experience.It also explores the affordances and constraints perceived by the teachers in this setting.Four technologically adept in-service mathematics teachers participated in the study.Data were collected through recordings of the online facilitated webinar sessions, where the teachers explored an authentic task involving a jack truss photograph in GeoGebra.An iterative inductive content analysis guided by the Sfard communication framework and categorization of teachers' professional knowledge was conducted.The findings indicate that content knowledge, pedagogical knowledge, and pedagogical content knowledge emerged.The DGE afforded manipulation, verification of justifications, time-saving explorations, and collaborative engagement.However, the teachers perceived that the DGE might automate problem-solving and reduce opportunities for independent reasoning compared to traditional methods.The study highlights the need for authentic, open-ended tasks in DGEs to guide areas for professional development.Future research should investigate the design of tasks that promote engagement and the development of professional knowledge.
Leena Ngonyofi Kanandjebo (Wed,) studied this question.