The International Lesson Study Seminar in Mathematics Education is an event that arose from a group of researchers involved in the subject, with the goal of broadening discussions on the potential of this professional development process to further promote teacher training and enhance students' mathematical learning.

Its first edition was held in 2021, by the Mathematics Teaching Research Group (GIEM), based at the University of Brasilia (UnB), and the Mathematics Pedagogical Practice Research Group (PraPeM), based at the State University of Campinas (UNICAMP), with the support of other groups, associations and higher education institutions. During this event, there were 6 (six) Round Tables and 63 (sixty-three) Scientific Communications, organized and presented in 14 (fourteen) Virtual Rooms, as well as 3 (three) Cultural Activities. Out of the 937 (nine hundred and thirty-seven) people who registered for the event, 648 (six hundred and forty-eight) regularly partook in the activities. This audience was made up of undergraduate and postgraduate students, teachers of Basic Education and Higher Education, representing 8 (eight) countries across the Americas, Europe and Asia. The Annals of the inaugural edition of the event are available at https://repositorio.ifes.edu.br/handle/123456789/1540.

The second edition was held in 2023 as a result of a partnership between the Mathematics Education and Technology Studies and Research Group (GEPEM@T) at the Federal University of the Southern Frontier (UFFS), the Mathematics Teaching Research Group (GIEM) at the University of Brasilia (UnB) and the Mathematics Pedagogical Practice Research Group (PraPeM) at the University of Campinas (UNICAMP), with the support of researchers from different Higher Education institutions. The II SILSEM schedule included 2 (two) conferences (opening and closing), 5 (five) Round Tables, 2 (two) Conversation Circles, organized in 7 (seven) Virtual Rooms involving teachers and researchers; 1 (one) Poster Session, in which 20 (twenty) papers were presented; 2 (two) Scientific Communication Sessions, organized in 27 (twenty-seven) Virtual Rooms in which 58 (fifty-eight) papers were presented; 2 (two) Book Launch Sessions, in which 10 (ten) books by Brazilian, Chilean, Portuguese and Spanish researchers were promoted; as well as 6 (six) Cultural Activities, incorporating elements of culture from all regions of Brazil. More than 1,600 people registered for the event, including researchers from Japan, Southeast Asia, Portugal, Spain, the United States and Latin America, particularly Brazil. There was a 71% increase in the number of participants of the event in comparison to the previous edition. The Annals of the second edition are available at https://portaleventos.uffs.edu.br/index.php/silsem/issue/view/174/57.

The third edition, eagerly awaited by both Brazilian and foreign researchers given the event’s importance for providing space for the promotion and socialization of Lesson Study in Mathematics Education, will be held on May 14, 15 and 16, 2025, in online format, and will be organized through the partnership between the Interfaces in Mathematics Education Research Group (GPIEM), from the Western Paraná State University (UNIOESTE), at the Foz do Iguaçu campus, the Mathematics Education and Technology Studies and Research Group (GEPEM@T) of the Federal University of the Southern Border (UFFS), the Mathematics Teaching Research Group (GIEM) of the University of Brasilia (UnB) and the Mathematics Pedagogical Practice Research Group (PraPeM) of the University of Campinas (UNICAMP), with the support of researchers from different Higher Education Institutions in both Brazil and abroad.

Lesson Study originated in Japan at the turn of the 19th to the 20th century, as a result of the educational changes implemented in the country, and is defined as a process of professional development for teachers based on two key principles: collaboration and reflection. It has been spread across all continents as a way of improving teachers' professional practices and students' learning.

Over the last few decades, Lesson Study, through a process of acculturation, has gained ground in various countries in America, Europe and Africa, as well as countries in Asia and Southeast Asia. As a result, it has been gaining traction on the international scenario as a promising professional development process in different areas of knowledge and at different levels of education.

In Brazil, Professor Dr. Yuriko Baldin, from the Federal University of São Carlos (UFSCar), is considered a pioneer in the promotion of Lesson Study in Mathematics Teaching, as well as having supervised the first dissertation (professional master's degree), by Professor Me. Thiago Francisco Felix, defended in 2010 at the Federal University of São Carlos (UFSCar), on the subject. Two other postgraduate papers inaugurated the development of research on this theme: the first dissertation (academic master's degree) by Professor Fellipe Gomes Coelho, supervised by Professor Claudia Coelho de Segadas Vianna and co-supervised by Professor Dr. Ana Teresa de Carvalho Correa de Oliveira. Ana Teresa de Carvalho Correa de Oliveira, defended in 2014 at the Federal University of Rio de Janeiro (UFRJ) and the first doctoral thesis (academic doctorate) by Professor Renata Camacho Bezerra, supervised by Professor Maria Raquel Miotto Morelatti, defended in 2017 at the São Paulo State University “Júlio de Mesquita Filho” (UNESP), in the campus of Presidente Prudente. Gradually, there has been a movement towards the growth and diffusion of Lesson Study in Mathematics Teaching, as well as research into this process of professional development, across all regions of the country.

Thus, SILSEM has become an important event that aims to disseminate Lesson Study around the world, bringing together researchers, teacher educators, teachers and future teachers who work or have worked with Lesson Study in Mathematics Teaching and/or in the Education of Teachers who teach Mathematics, as well as all those who are interested in learning about this process, seeking ways to develop it in their professional and/or research practices.

In its third edition, SILSEM intends to:

1)    to bring together national and international researchers to discuss Lesson Study in the Education of Teachers that teach Mathematics;

2)    to discuss the possibilities of Lesson Study to promote changes in teachers' practices and students' learning, and 

3)    to bring together researchers from around the world who are investigating the subject of Lesson Study in the process of teaching and learning Mathematics at all levels of education.

The III SILSEM schedule is being put together so that participants coming from different countries can share their experiences with/in Lesson Study in Mathematics Teaching and get to know other experiences. To this effect, the event will include Conferences and Round Tables, Conversation Circles, Scientific Communication Sessions and Book Launch Sessions in Portuguese, English and Spanish. The event's thematic areas involve the following topics:

(a) Teaching and Learning Mathematics in Basic Education; 

(b) Teaching and Learning Mathematics in Higher Education; 

(c) Initial Training for Mathematics Teachers; 

(d) Continuous Education for Mathematics Teachers; and 

(e) Professional Development of Mathematics Teachers and Teacher Educators.  

The types of paper presentation will be:

(a) Long Scientific Communication;

(b) Short Scientific Communication; and

(c) Conversation circle (experience report).

The event will receive proposals for completed and ongoing research, as long as they present partial data and work with Lesson Study in the process of teaching and learning Mathematics in its different aspects.

In order to make the event as inclusive as possible, we will have Libras interpreters taking part in the activities, and all the information will be available on the website in three languages: Spanish, English and Portuguese.