ORIENTAÇÕES DIDÁTICAS PARA O ESTUDO DO CONCEITO DE PROPORCIONALIDADE BASEADAS NAS DUAS RÉGUAS PARA CÁLCULO

The concept of proportionality is present in the student's life from Elementary School to High School, so it is necessary for the teacher to consider different types of resources that will help the student in understanding this concept. In view of this, the Two Rulers for Calculation, an instrument designed by William Oughtred (1574-1660) in the 17th century, is characterized as one of these resources, coming from the History of Mathematics, which can contribute to the construction of mathematical knowledge of proportionality. Thus, through qualitative descriptive and documentary research, we intend to present a proposal for an activity involving the concept of proportionality for the Final Years of Elementary School, through the handling of a historical mathematical instrument. Therefore, when presenting the concept of direct proportion and the handling of rulers, the student can mobilize other mathematical concepts that are linked to proportionality, such as the orders of units and tens of the decimal numbering system, as well as the notion of ratio and the equality between two ratios, forming a proportion, leading the student to relate what is seen on the instrument to what is worked on by the teacher in the classroom, thus contributing to the construction of knowledge of proportionality.