The aim of this study was to investigate how teaching with visual representations influenced students’ conceptual reasoning about fractions as part-whole relationships in grade 4. The study addressed how students’ performance changed between a pre-test and a post-test, how their reasoning developed, and how they used and related different representations.

The study was conducted as a practice-based intervention using a combination of quantitative and qualitative methods. Data were collected through a pre-test and a post-test in connection with a teaching sequence where visual representations, such as circle models, rectangular models, and number lines, were integrated into instruction. The theoretical framework was based on Raymond Duval’s theory of semiotic representations.

The results indicated improved performance and a shift from whole-number-based reasoning towards a greater focus on part-whole relationships. Students increasingly used visual representations and showed a developing ability to coordinate visual and symbolic forms. Some difficulties remained, particularly in tasks requiring comparison and conversion between representations. The study concluded that systematically integrating multiple representations may support students’ conceptual understanding of fractions.