We examine aspects of professional collaboration in a lesson study conducted with mathematics teachers from the final years of basic education belonging to public schools in the State of Rio Grande do Sul, Brazil. The lesson study, conceived as a professional development approach focused on collaboration and reflection, took place in the 2nd semester of the 2019 school year, organized in 12 meetings of 2.5 hours each, and involved 8 tenured teachers in schools belonging to the 15th Regional Education Coordination of that State. The empirical material of the study consisted of the field notes produced at each meeting of the lesson study, the data from an initial questionnaire administered to the teachers, as well as the transcription of the audio recordings of the interviews with the participants and of the sessions of the lesson study. The qualitative and interpretative analysis showed that the dynamics of the lesson study enhanced several basic aspects of collaboration, namely mutual encouragement and support, cooperation and shared reflection.

ResumoO desenvolvimento profissional abarca distintas dimensões, entre elas a colaboração, que oportuniza aos professores partilhar ideias, valores, experiências e refletir sobre a prática profissional. Uma abordagem de desenvolvimento profissional baseada na colaboração é o estudo de aula (lesson study). Nesta perspectiva, realizamos uma investigação visando evidenciar e compreender os aspectos da colaboração profissional vivenciados por um grupo de oito professores de matemática dos anos finais do ensino fundamental, participantes em um estudo de aula. O estudo de aula foi desenvolvido de agosto a dezembro de 2019, estruturado em 12 encontros quinzenais de 2,5 horas cada, e envolveu professores de escolas públicas estaduais pertencentes a 15ª Coordenadoria Regional de Educação do Rio Grande do Sul, Brasil. O material empírico constituiu-se dos registros produzidos nos encontros, transcrição das gravações de áudio das sessões do estudo de aula, bem como das notas de campo produzidas na aula de investigação (terceira etapa do estudo de aula). A análise, qualitativa e interpretativa, evidenciou três aspectos da colaboração profissional: apoio e incentivo mútuo, partilha e diálogo. O apoio e incentivo mútuo foram muito valorizados pelos professores porque criaram as condições para que todos pudessem participar do processo e se envolvessem em todas as etapas. A partilha oportunizou aos professores partilhar expectativas, angústias, objetivos e experiências de sala de aula. O diálogo os oportunizou experimentar um processo formativo que valorizava a voz dos participantes e a negociação de decisões. Esses aspectos, em relação de complementaridade, fortaleceram as ações e interações entre os professores participantes e a confiança entre os pares, favorecendo aprendizagens profissionais relacionadas à docência em matemática. Palavras-chave: Colaboração Profissional. Lesson Study. Estudos de Aula. Desenvolvimento Profissional de Professores. Formação de Professores. AbstractTeacher Professional development encompasses important dimensions, such as collaboration, which gives teachers the opportunity to share ideas, values, experiences, and reflect on professional practice. A collaborative approach to professional development is lesson study. In this perspective, we carried out a research aiming to highlight and understand the aspects of professional collaboration experienced by a group of eight mathematics teachers from the final years of elementary school, participating in a lesson study. The lesson study was carried out from August to December 2019, structured into 12 meetings of 2.5 hours each, and involved teachers from state public schools belonging to the 15th Regional Education Coordination of Rio Grande do Sul, Brazil. The research empirical material consisted of audio recordings produced in the meetings, transcription of audio recordings of the lesson study sessions, as well as researcher field notes produced in the research lesson (third stage of the lesson study). The analysis, qualitative and interpretive, highlighted three aspects of professional collaboration: mutual support and encouragement, sharing, and dialogue. The mutual support and encouragement were highly valued by the teachers because they created the conditions for them to participate in the process and get involved at all stages. The sharing gave the teachers the opportunity to share expectations, anxieties, goals, and classroom experiences. Dialogue gave them the opportunity to experience a teacher education process that valued the voice of the participants and the negotiation of decisions. These aspects, in a complementary relationship, strengthened the actions and interactions between the participating teachers and the trust among peers, favoring professional learning related to mathematics teaching. Keywords: Professional Collaboration. Lesson Study. Teacher Professional Development. Teacher Education.