Background: Mathematics plays a critical role in nurturing students' logical reasoning and problem-solving capabilities, especially in geometry, which often poses challenges for elementary learners. Previous observations at SD Djama’atul Ichwan Surakarta revealed that third-grade students struggled to understand the concept of flat shapes (plane geometry) and to apply relevant strategies in solving word problems. This deficiency highlighted the need for an instructional approach that bridges conceptual gaps and enhances problem-solving proficiency. Aims: This study aimed to investigate the effectiveness of Schema-Based Instruction (SBI) in improving elementary students' problem-solving skills in geometry, specifically in the context of flat shape word problems. Methods: The research employed a classroom action research (CAR) design conducted over two cycles. The participants were 31 third-grade students from SD Djama’atul Ichwan during the 2018/2019 academic year. Data were collected using tests, observations, interviews, and documentation. Triangulation techniques and Miles-Huberman’s interactive model were used for data analysis to ensure validity and depth. Results: Findings showed a significant improvement in students' problem-solving skills. Initial classical mastery was only 10%, which increased to 87% by the end of Cycle I and exceeded the 80% research target in Cycle II, with final meetings reaching up to 94% classical mastery. Conclusion: The implementation of Schema-Based Instruction significantly enhanced students’ ability to solve geometry word problems. By guiding learners through structured schemata, SBI enabled better comprehension, strategic organization of information, and accurate solution processes. Its visual and stepwise nature aligns with the cognitive characteristics of elementary students, especially at the concrete operational stage. The results underscore SBI's potential as an effective pedagogical tool in primary mathematics education. Moreover, this study contributes to instructional design literature by validating SBI as a contextually adaptable and scalable strategy for fostering mathematical thinking. Future research could explore its long-term impact and application across broader mathematical domains.
Syarif et al. (Wed,) studied this question.