<![CDATA[Background: The teaching of compound probability in vocational high schools continues to face challenges due to the abstract nature of the concepts and the limited integration of mathematical content with students’ real-life experiences. These conditions often hinder students’ conceptual understanding and learning engagement. Therefore, innovative instructional media that combine technological advancement with contextual learning approaches are needed. Aims: This study aimed to develop a mobile learning application based on the Realistic Mathematics Education (RME) approach for teaching compound probability and to evaluate its validity, practicality, and effectiveness. Methods: This research employed a research and development (R&D) design using the ADDIE model, which consists of analysis, design, development, implementation, and evaluation stages. The participants included 35 eleventh-grade students from a vocational high school in Malang, Indonesia. Data were collected through validation sheets, student and teacher response questionnaires, and learning achievement tests. The developed application was validated by a mathematics education lecturer and a mathematics teacher. Results: The findings indicated that the developed mobile learning application achieved a high level of validity, with an average score of 86.37%. The practicality assessment showed positive responses from both students (84.09%) and the teacher (85.71%). Furthermore, the effectiveness test revealed that 85.71% of students achieved the minimum learning mastery criterion, with an average achievement score of 86.49. Conclusion: The RME-based mobile learning application was found to be valid, practical, and effective for teaching compound probability in vocational high schools. By integrating contextual problems, interactive multimedia, and flexible learning opportunities, the application has the potential to enhance students’ mathematical understanding and support innovative mathematics instruction in the digital era.]]>
