Aquisi？？o das opera？？es combinatórias por alunos pré-universitários através de uma interven？？o de ensino

this article presents the main results of a research study relating to a teaching and learning intervention for combinatorial operations in a 12th grade class. the teaching intervention carried out during school year 2008/2009 focused on the sequencing of operations based on their level of difficulty, on the previous ideas of students in relation to the operations, on learning by discovery and on group work. once the teaching intervention had been carried out, a two stage exam was applied, designed to evaluate the acquisitions of students in combinatorial operations relating to strategies used, performance and mistakes. in general, the results reveal that the teaching intervention was effective in developing combinatorial reasoning abilities.