"Close the Box" Software as a Teaching Resource for the Development of Mental Calculation

Abstract

This article explores the potential of the digital software "Close the Box" as a teaching tool for teaching the additive field to students in the 2nd year of the first cycle of Elementary School. A qualitative and interpretative methodological approach was adopted, in which the researchers analyzed their observations and understandings in light of theoretical references on the use of games in teaching and the additive conceptual field. The results indicate that the use of the game encouraged students to reflect on their strategies when solving problems involving calculations. Situations involving composition were the ones that students found easiest. In addition, interaction with colleagues allowed them to observe different calculation methods, progressively incorporating new approaches. Additionally, the study highlights the Lesson Study methodology used, which not only aimed to improve student learning, but also the professional development of the teacher. The activity with "Close the Box" allowed the teacher to deepen her understanding of students' reasoning in the additive field. Finally, we suggest the production of future research to investigate the appropriation of curricular knowledge by teachers using the Lesson Study methodology and we hope that this report will contribute to other studies and pedagogical practice.