Fidelity-to-Function in Cor-Yu: Adapting a Malay Culture-Based Discovery Learning Model in Grade 7 Geometry

Culturally grounded mathematics models can retain visible cultural forms while weakening the participatory or mathematical functions that those forms are intended to support. This study examines Cor-Yu, a six-stage Malay culture-based discovery learning model for Grade 7 geometry in which pantun-derived values—questioning and responding, linguistic politeness, courage to express ideas, and responsiveness to others—structure mathematical interactions. A focused secondary implementation analysis within educational design research examined two successive four-lesson trials at SMP Negeri 3 Kisaran, Indonesia (n = 32 and n = 34), focusing on properties and perimeter and area of two-dimensional shapes. Evidence comprised two-observer intended-operational fidelity ratings, focal-student activity observations, teacher-enactment ratings, student responses, and a revision log documenting 16 modifications. Overall fidelity was 3.45 in Trial 1 and 4.41 in Trial 2 on a five-point scale, with the social system showing the largest descriptive difference (3.35 to 4.44). Teacher enactment ratings were 3.36 and 3.74, respectively. Student-activity distributions in Trial 2 were descriptively closer to the model’s predefined ideal allocations across all five categories, while student responses remained highly positive. Because the trials used different intact classes and the same teacher, these patterns are descriptive rather than causal. Fidelity-to-function is proposed provisionally as a principle for assessing whether adaptations preserve culturally recognizable, dialogic, relational, and mathematical functions rather than requiring literal uniformity of form.