Estratégias de cálculo mental de alunos da 5ª série/6º ano do ensino fundamental

• Autor(a) principal: Santos, Daniel Moreira dos
• Data de Publicação: 2014
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/1148
• topic: Elementary school; Addition and subtraction; Mental calculation; Strategies of mental calculation; Numerical sense; Mathematics; Cálculo mental; Estratégias de cálculo mental; Sentido numérico; Adição e subtração; Educação; Adição; Aprendizagem – Matemática; Ensino fundamental; Matemática; Matemática – Estudo e ensino; Subtração; 37

The major objective of this research was to investigate strategies of mental calculation used byelementary school students in the fifth and sixth grade to solve addition and subtraction equations. For that purpose, we sought to answer the following questions: Which strategies of mental calculation do fifth and sixth-grade students use to solve addition and subtraction equations? What is the relationshipbetween the type of calculation and the strategy adopted for the solution? To answer these questions we followed a quantitative methodology configured as ethnographic case study. Our fieldwork was developed with a group of elementary students in the fifth and sixth gradeat a state public school in the city of Serra. The research recurred from May to December 2013. Eight students solved a diagnostic activity composed of four sequences of mental calculation: basic facts of numbers 5, 10, 20 and 100, among additions and subtractions close to these results.All the students also took part in the interviews.Out of eight students, we selected data of three students who took part in other stages of the research. As source to collect data,we used every record made by the students during group observation, diagnostic stage and didacticintervention stage, as well as notes from our fieldwork notebook and audio recording. We used the strategies identified by Beishuizen (1997), Klein and Beishuizen (1998), Thompson (1999, 2000) and Lucangeli et al (2003) as analysis categories. Through the data analysis, we verified that the students decided on a certain strategy of mental calculation according to the type of calculation sequence, the arithmetic operation (additionor subtraction) and their emotional condition during the activity. Two combined strategies were observed:the mental algorithm and strategies of finger counting for most of the calculations. The use of mental algorithm proved excess mental overload; with the student conducting it from the left to the righ – similarly to the strategy of numerical decomposition - for some cases of addition without carrying, the mental algorithm functioned only to support numerical display.Data in this study indicate: (i) teachers should be required to work sistematically with basic numerical facts for addition and subtraction via mental calculation during classes; (ii) teacher should be required to provide students with authentic strategies of mental calculation to make them not dependable on mental counting or algorithm – rarely successfully executed; (iii) it is important to interview each student in order to understand and assess their development in mental calculation tasks.