Teacher Practice

To contribute to understanding how teachers can develop geometrical understanding, we report on the discursive development of teachers’ geometrical reasoning through instrument appropriation while collaborating in an online dynamic geometry environment (DGE). Using the theory of instrument-mediated activity, we analysis the discourse and DGE actions of a group of middle and high school mathematics teachers who participated in a semester-long, professional development course. Working in small teams, they collaborated to solve geometric problems. Our results show that as teachers appropriate DGE artifacts and transform its components into instruments, they develop their geometrical knowledge and reasoning in dynamic geometry. Our study contributes to a broad understanding of how teachers develop mathematical knowledge for teaching.

We report on a case study that seeks to understand how teachers’ pedagogical interventions influence students’ instrumentation and mathematical reasoning in a collaborative, dynamic geometry environment. A high school teacher engaged a class of students in the Virtual Math Teams with GeoGebra environment (VMTwG) to solve geometrical tasks. The VMTwG allows users to share both GeoGebra and chat windows to engage in joint problem solving. Our analysis of the teacher’s implementation and students’ interactions in VMTwG shows that his instrumental orchestration (Trouche, 2004, 2005) supported students’ instrumentation (Rabardel & Beguin, 2005) and shaped their movement between empirical explorations and deductive justifications. This study contributes to understanding the interplay between a teacher’s instrumental orchestration and students’ instrumentation and movement towards more deductive justifications.

On July 15-17, 2012 the United States National Commission on Mathematics Instruction and Seoul National University held a joint Korea-U.S. workshop on Mathematics Teaching and Curriculum. The workshop was organized to address questions and issues related to math teaching and curriculum that were generated by each country. This report summarizes the presentations and discussions at the workshop.

An electronic teacher guide (eTG) was developed to determine whether a digital guide could better support teachers in implementing an inquiry-based curriculum and in enhancing their practice. Developed as a proof-of-concept exemplar, features of the eTG support high school teachers in planning, implementing, and modifying innovative instructional materials and in developing more ambitious teaching practices.

To examine the value of the electronic teacher guide (eTG) as a curriculum planning and teaching tool,
it was important to study it in the contexts of teachers’ actual planning, teaching, and reflecting.
This paper described two descriptive case studies.