An overview of mixed type situations in the Brazilian national high school exam (ENEM) tests

Abstract: This research aims to identify and classify mixed-type situations, associated with the affine function, present in Enem tests. The 2020 Enem tests were analyzed and 10 possible situations were identified to be written in the form f ( x ) = ax + b . Each situation was analyzed in terms of data presentation, resolution structure, and classified based on the combination of classes of additive and multiplicative conceptual fields, as proposed in the Conceptual Fields theory, which supports this research. Among the classes identified in the corpus, the most frequent one was simple double proportion and composition of measures, with three situations. For most students who take Enem, access to mathematical knowledge comes from the classroom; therefore, knowing the different classes of mixed-type situations is in the teacher's interest to provide students with the construction of the concept of the affine function.