Raciocínio proporcional e algébrico de alunos ao resolverem uma tarefa probabilística.

We examine the strategies and errors in the responses of a group of students in the sixth grade of Primary Education (11-12 years old) to a task that requires determining the composition of an urn whose probability of success is the same as in another task in which the ratio between favorable and unfavorable cases is known. The results show that students were successful in obtaining the composition of the urn, but encountered difficulties in arguing their solutions. Few traits of proto-algebraic reasoning are evidenced. The potential of the probabilistic context to advance in the development of proportional reasoning is concluded.