Improving instruction and learning in arithmetic in Grade 5 through action research

This article presents an action research project conducted in collaboration between university researchers and elementary school teachers, aimed at enhancing arithmetic proficiency among fifth-grade students in Sweden. Grounded in the Integrated Theory of Numerical Development, the project focused on strengthening students’ understanding of numerical magnitude and arithmetic operations through structured, research-informed instruction. Weekly collaborative planning and reflection meetings supported the iterative development of teaching strategies, emphasizing conceptual and procedural knowledge, arithmetic fluency, and the use of number lines and comparison strategies such as residual thinking and reference points. The action research project was implemented in schools located in low socio-economic areas and compared with a control school in a high socio-economic context. A mixed-methods approach was used, combining classroom observations with pre- and post-project assessments. Quantitative analyses revealed significantly greater gains in number sense and arithmetic proficiency among students in the action research schools. The study demonstrates how action research can bridge the gap between theory and practice, promote professional development, and contribute to enhance educational outcomes. It also highlights the value of sustained collaboration between practitioners and researchers in designing responsive instruction and offers a model for integrating formative assessment and reflective teaching into everyday classroom practice.