This investigative proposal intends to give an account of the process, the findings and results that emerged during our practice as research teachers, which was held in the educational institution José Félix de Restrepo Vélez, specifically in second grade, whose students live in the municipality of Sabaneta where the campus is located. The research is qualitative; from the ethnographic design type, we applied the technical participant observation and we implemented as tool, the class protocol as their guiding teaching room which the didactic units focused on learning the concepts of addition and subtraction were developed, applied in the solution of mathematical problems. Records and data analyzed were the productions of the students and their analysis was performed taking as main reference the perspective historic-cultural since supplemented by other theorists postulated allowed us to understand important aspects of the mathematics teaching and learning. The results obtained from this experience allowed us to demonstrate how the structuring of our teaching allowed students to take a cognitive leap (Vigotsky, 1983), in learning the concepts of addition and subtraction applied in solving mathematical problems.