Um estudo sobre a abordagem da subtração de números naturais em livros didáticos de matemática utilizados na Rede Municipal de Ensino de Paranatama

Abstract

The present work aims to present the results of a didactic analysis with a specific focus on the mathematical operation subtraction with natural numbers; using Gerard Vergnaud's Theory of Conceptual Fields as a theoretical contribution. The students' difficulties in relation to this operation are recurrent and diverse. Knowing that textbooks are instruments to assist in the teaching-learning process, but do not always promote strategies for developing the skills necessary to solve different situations, we seek to understand how mathematics textbooks for the early years address situations involving the operation fundamental subtraction with natural numbers. We specifically analyzed activities and explanations and didactic resources that involve the actions of removing, comparing and completing proposals in the chapters that deal with the theme and in the teacher's manual of the 4th and 5th year elementary school books, used in the municipal education network of city of Paranatama-PE. The research is of the documentary type with a qualitative approach and with a certain quantitative aspect. The method used is inductive, as there are no pre-formed concepts, nor does it consider previous hypotheses. The data obtained showed that the number of situations that address the ideas of removing, comparing and completing is insufficient in both volumes. Among the suggested calculation strategies, we highlight the use of the conventional algorithm using the higher order or “loan method”, and also subtracting the same value in the minuendo and subtrendendo, especially when there are zeros in the minuendo; mental calculus, rounding and the number line were also used to develop a reasoning strategy. Regarding resources, the numerical line, the calculator and the gold material stood out.