Currently, the system learning evaluations to measure the quality of its output, which aims to better diagnosis and prognosis of the levels of cognitive performance of schoolchildren, said in school practice some inaccuracies, for example, the introduction of the category performance levels cognitive is not well understood among teachers, especially around the degrees of similarity and difference with respect to the known levels of assimilation of the content. Shedding light on these phenomena which occur in school practice and clarify some aspects through the subjects of Mathematics and Spanish Language is the essence of the work DEVELOPMENT If cognition is understood the mechanism of knowing, then the cognitive activity is the action or set of actions performed in order to know an object, phenomenon or appearance. Cognitive activity results in the assimilation of knowledge and the possibilities of applying it to the most diverse situations, therefore assimilation can be analyzed as a process and as a result. This process coincides with the development of cognitive activity, for its part when analyzing assimilation, as a result, reference is made to the volume and quantity of knowledge, and the degree of development of the skills and habits that the students demonstrate they have acquired activity. In the literature recognizes the existence of three levels of assimilation through which passes the whole process of learning of schoolchildren. These levels are: Level Reproductive: Characterized by breeding activities of the object of knowledge. Application layer: It qualifies for the application of knowledge and skills in the practical sphere. . .