The goal of this study was to investigate problem solving: its possible contribution to the learning of basic operations with fractional numbers, with 5th grade students from the Piedra de Leon Sotara Educational Institution - Casas Nuevas. The main objective of the research was to describe the contribution of problem solving to the learning of basic operations with fractional numbers. The methodology used was framed from the implementation of a didactic unit which was designed in three sequential moments. Location, in this moment, the instrument of previous ideas was applied to the students, the next moment is called dislocation, according with the Miguel de Guzman’s model, different activities and problem situations were used in the learning process, the work developed achieved that the students understood individually and collectively the proposed heuristics; Finally, the last moment refocusing, we verified that the incidence of solving problems in overcoming epistemological obstacles on learning basic operations with fractional numbers was significant, because students observed the application of these numbers, including operations in daily life and were able to recognize the importance of learning the basic operations like addition, subtraction, multiplication and division. In addition to achieving an advance in the generation of critical thinking to solve problems oriented from the model presented by Miguel de Guzman, in its social context and in other life situations.