Year 2 inaccurate but flexible mental computers: Teacher actions supporting growth

The Year 1-10 Mathematics Syllabus, recently implemented in Queensland’s schools introduces mental computation as the main form of computation with written computation emphasising students’ self developed strategies (QSA, 2004). To facilitate the incorporation of mental computation into the curriculum a teaching experiment that adopted a case study design was conducted. A Year 2 teacher was provided with a series of professional development (PD) sessions that incorporated the mathematics of mental computation and the use of support materials. She then used this knowledge to develop (with the assistance of the researcher) a series of 8 half hour lessons delivered over an eight week period. This paper reports on the pre- and post-study interview results of two of her students. Their selection was based on responses to questions that probed for accuracy and flexibility of strategy. During the pre-study interview both students demonstrated inflexible and inaccurate mental computation. On post-interviewing the students remained inaccurate; however, their repertoire of strategies had developed such that they were categorised as flexible mental calculators. Close examination of teacher actions, including engaging students in mathematical discussions, the use of representations and teacher consideration of the mental computation process of proficient mental computers all appear to have supported student growth. Further growth in accuracy as well as flexibility, although seen in other students in the class was not evident with these two students. Close examination of error patterns will further support teacher acquisition of content and pedagogical knowledge essential for the teaching of mental computation.