1 MATHEMATICAL COMMUNICATION: TEACHERS’ RECOGNITION OF THE SINGULARITY OF STUDENTS’ KNOWLEDGE António Guerreiro 2 , João Pedro da Ponte 3 and Lurdes Serrazina 4 2 School of Education and Communication, University of the Algarve (Portugal) 3 Institute of Education, University of Lisbon (Portugal) 4 School of Education, Polytechnic Institute of Lisbon (Portugal) This paper discusses the role of collaborative work in fostering social interactions in the classroom, how teachers value such interactions to develop the modes of communication, and in the interaction patterns centered on students' individual knowledge. Data were collected in the context of collaborative work involving a researcher and three participating teachers. The development of interactions among the students themselves and between them and the teachers, along with the recognition of the students’ singular mathematical knowledge, led to the adoption of reflexive and instructive modes of communication and also to the extraction and discussion patterns in mathematical communication. Key words: mathematical communication; modes of communication; interaction patterns; teaching practices; collaborative work. INTRODUCTION Mathematical communication is as much part of mathematics classes as mathematics itself. Such communication takes different forms according to the teachers’ conceptions of the nature of mathematics, its teaching and learning and the role of communication in their professional practices. Teachers’ positions concerning the nature of mathematics as a way of understanding society are translated into forms of mathematical communication, considering the existence of several strategies and singular forms of mathematical knowledge in the classroom. Mathematical communication as the foundation of the teaching and learning process is based on the recognition of social interactions in the classroom between the teacher, the students and mathematical knowledge (Sierpinska, 1998) and considers discourse as a social practice (Godino & Llinares, 2000), where the role played by all actors in the negotiation of mathematical meanings is of the utmost importance. In this perspective, mathematical communication is a social process in which participants interact, exchanging information, influencing each other, taking up the attitude of the other and, simultaneously, expressing and asserting his or her singularity (Belchior, 2003; Mead, 1992). Teaching becomes the organization of an interactive and reflexive process, where the teacher is continuously engaged in updated and differentiated activities with students (Cruz & Martinón, 1998) and where students become aware of their cognitive and affective processes, mobilizing them for learning (Ponte, Brocardo & Oliveira, 2003).