Scientific research in mathematics didactics has described and analyzed the processes of learning mathematics. After detecting the students’ errors and difficulties in curve fitting and interpolation, a didactic intervention in a numerical calculus course used a script designed to learn numerical calculations using the technologies implemented in this topic, presented in this work. Based on Godino and colleagues’ Ontosemiotic Approach (OSA) framework, a qualitative perspective and an interpretive paradigm were used to establish its didactical suitability. The “Curve fitting and interpolation” didactic intervention was executed in a class of 4th-year higher education students in Mathematics at a Brazilian Federal Institute. Based on the results, the OSA-didactic suitability of the intervention in the Mathematics degree class was characterized. It was concluded that the overall didactic suitability of the “Curve fitting and interpolation” classes was considered high since they managed to overcome many semiotic conflicts detected. The epistemological and cognitive components were balanced in these presential classes. In addition, the face-to-face environment favored observations of the students’ gestures (emotions and attitudes) in these presential classes, access to technological tools, the intense dialogue between students and student/teacher in explanations, and carrying out tasks (individual and group) contributed to improvements in the affective, interactional and emotional components. We also observed the good relationship and interest of the students in the class with the objects of the subject under study and their technological applications (scientific and technological), which highlighted the mediational facet and, indirectly, boosted other components.