Rahmi Hayati
This study aims to develop a Coding–Realistic Mathematics Education learning model based on Acehnese culture that is valid, practical, and effective in improving elementary school students' numeracy literacy, 21st-century competencies (4Cs), and psychosocial recovery in post-disaster settings. The study employed the ADDIE development model, consisting of the Analysis, Design, Development, Implementation, and Evaluation stages. During the analysis stage, learning needs, students' characteristics, post-disaster psychosocial conditions, and the potential of Acehnese culture as a contextual basis for mathematics learning were identified. The design stage produced the syntax of the Coding-RME learning model by integrating the principles of Realistic Mathematics Education, simple coding activities, and Acehnese ethnomathematics. The development stage resulted in teaching modules and student worksheets that were validated by subject matter experts, media experts, Acehnese culture experts, and educational psychology experts. The implementation stage involved a limited trial conducted with students at UPTD SD Negeri 1 Bireuen. Data were collected using validation sheets, observation forms, numeracy literacy tests, psychosocial questionnaires, and 4C competency assessment instruments. The findings indicate that the Coding-RME model achieved a validity level of 91.2%, categorized as highly valid, and a practicality level of 88.4%, categorized as practical. The evaluation results showed an improvement in students' numeracy literacy with an N-Gain score of 0.52 (moderate category), while the average score for 4C competencies reached 4.35 (good category), and the psychosocial aspect achieved an average score of 4.45 (high category). These findings demonstrate that integrating coding, Realistic Mathematics Education, and Acehnese culture creates a contextual, collaborative, and meaningful mathematics learning environment while supporting students' psychosocial recovery after disasters. Therefore, the Acehnese culture-based Coding-RME model can serve as an innovative alternative for developing 21st-century mathematics learning that is adaptive to students' social, cultural, and psychological contexts.