The purpose of this case study was to examine a third-grade teacher’s effective use of mathematical discourse in the classroom setting. The study offers insights into the following research questions: (1) How does a teacher’s engagement in mathematical discourse communities influence her practice and self-efficacy as a mathematics educator? (2) What teacher moves support or hinder effective student discourse in mathematics? (3) How does the facilitation and maintenance of discourse communities enhance mathematical understanding for the teacher and the students?

Four main sources of data were collected: 18 video-taped observations, including researcher field notes; pre-and-post observation discussions with the teacher; and three audio-taped interviews with the teacher. Data were analyzed using constructed grounded theory and situational mapping. These methods allowed the researcher to engage in simultaneous data collection and analysis, using memo-writing as a way to form hunches around the data which were then explored in collaboration with the teacher.

The analyses indicated the teacher engaged in a variety of pedagogical practices that moved her learners from the simple implementation of social norms to a higher level of discourse that supported their engagement in sociomathematical norms. These moves included the following: building a community of learners, encouraging students as mathematicians, asking genuine questions, pressing students and encouraging disequilibrium, promoting risk-taking, making teacher decisions transparent to students, and decentralizing her teaching. Factors that hindered student discourse included time, teacher language around the use of “I” statements, and teacher content knowledge.

Through the use of these pedagogical practices and the integral part the teacher and students played in the creation and growth of their discourse community, student and teacher beliefs towards mathematics shifted and the teacher’s self-efficacy was enhanced. Episodes from this classroom indicated mathematics instruction and teacher moves were purposefully planned and implemented, thus promoting student discourse. The mathematical understandings and beliefs of the teacher and her students were influenced by their participation in a well-established mathematical discourse community.

The study shows how engaging in mathematical discourse can be one of the foundational cornerstones from which teachers and students can begin to construct a deeper understanding of the world of mathematics.