This study described how and why a Korean elementary teacher taught mathematics as he did. Specifically, the study sought to describe his beliefs about the teaching and learning of mathematics and relate them to patterns of classroom interaction and norms. An ethnographic inquiry guided the study of one third grade 10-year veteran teacher over three months in Korea. Through participant observation, the researcher observed Teacher Lee's teaching paying special attention to the mathematics lessons for one class of 45 students daily Monday through Saturday. Formal and informal interviews were used to collect data on the teacher and 17 of his students as well as other teachers (such as four teachers in the third grade), two principals, two mothers, and three beginning teachers. In addition to participant observation and interviews, a variety of documents were also collected, including newspapers, articles from journals, test items used in the teacher's classroom, daily worksheets, curriculum guide book, mathematics textbook, the school's newspaper. All videotapes and audiotapes were transcribed for inductive analysis. The analysis generated six major themes of the teacher's beliefs about the teaching and learning of mathematics and how those beliefs impacted the interactions and norms: (a) behave orderly, think freely; (b) teaching mathematics with understanding; (c) manipulative activities and games; (d) discourse-oriented teaching practices; (e) mathematical tasks; and (f) professional development. The teacher's beliefs about the teaching and learning of mathematics were closely related to the interaction patterns and classroom norms. This close relationship implies that identifying interaction patterns and classroom norms may shed light on understanding teachers' beliefs and teaching practices. The teacher's study group activity was a major professional development factor in promoting the consistent relationship. Implications and recommendations included (a) the need for more study of classroom norms and interactions as practical knowledge of teaching mathematics, (b) the need for investigating the effect of a study group to support teacher change, (c) the importance of the relationship between pedagogical content knowledge and teachers' beliefs, and (d) the need for more study of classroom management for teaching mathematics using understanding and discourse as an instructional strategy. / Graduation date: 2000