Abstract. The flipped classroom model has emerged as an effective strategy for enhancing student engagement and conceptual understanding in mathematics education. This study developed and validated flipped classroom learning materials for Mathematics in the Modern World (MMW) to address students’ difficulties with abstract and conceptual topics. Using the Successive Approximation Model (SAM), a diagnostic assessment was first conducted among 100 first-year college students to identify the least mastered lessons: Where is Mathematics, How Mathematics is Done, Characteristics of the Language of Mathematics, and Some Elementary Logic, with correct response rates ranging from 20% to 40%. Based on these findings, four instructional modules were designed and later evaluated by 80 purposefully selected students and seven mathematics experts. The evaluation focused on four criteria: content, design, features, presentation, organization, and assessment tools. Descriptive statistics revealed that students and experts rated the materials as “good” (overall mean = 3.44), citing clarity, engagement, and alignment with learning objectives. Thematic analysis of qualitative feedback highlighted strengths in structure and multimedia use while recommending enhancements such as authentic assessments, interactive tasks, and standardized rubrics. The study concludes that the developed instructional materials are pedagogically sound and suitable for flipped learning environments, with suggestions for further refinement and broader implementation.

Keywords: Flipped classroom; Higher education; Instructional materials; Mathematics in the Modern World.