This article is the product of a research concluded and funded by the University of Quindío and aimed to identify historical, epistemological, didactic and cognitive elements that intervene in the learning of the concept of perimeter and area; the study was carried out during 2014 with students of the Quindiana Foundation of Integral Care in the city of Armenia Colombia, who have cognitive difficulties or Down Syndrome. To do this, the theoretical framework of Brousseau’s didactic situations and didactic engineering methodology was used, through the design and application of didactic sequences as support for inclusion in the educational system from an interactive mediation of learning and teaching mathematics. The results show that people with Down Syndrome also manage to learn mathematical notions and concepts at a different rate.