<![CDATA[This study aims to: 1) Describe the application of Bruner's learning theory stages to improve mathematical concept understanding among fourth-grade students at Kanisius Kedawung Elementary School in the 2024/2025 academic year; 2) Improve mathematical concept understanding through the application of Bruner's learning theory stages among fourth-grade students at Kanisius Kedawung Elementary School during the 2024/2025 academic year. This study employs a Classroom Action Research approach, involving the classroom teacher and 22 students as participants. Data were collected through observation, interviews, documentation, and tests, with triangulation used to ensure data validity. Interactive data analysis methods were used throughout the study. The results showed a consistent improvement in students' mathematical concept understanding performance, with the average score increasing from 71.25 in the first cycle to 84.54 in the second cycle. Classical completeness also improved, from 59.09% in cycle 1 to 86.36% in cycle 2. This study concludes that: 1) Bruner's stages of learning theory can be effectively applied; and 2) these stages significantly improve fourth-grade students' mathematical concept understanding. Theoretically, these findings provide insights into the application of Bruner's Learning Theory stages in mathematics teaching. Practically, the application of Bruner's Learning Theory stages demonstrates clear benefits and positive impacts, making it a useful reference for future educational research.]]>
