Etnomatematika Perhitungan Hari Baik: Analisis Konsep Matematis dalam Tradisi Adat Desa Sadabumi

Abstract

This study explores the mathematical concepts embedded in the traditional practice of determining auspicious days for significant life events such as weddings, circumcisions, thanksgiving ceremonies, and house construction within the cultural context of Sadabumi Village, Majenang, Cilacap. The urgency of this research stems from the gradual marginalization of local traditions and the risk of cultural knowledge loss amidst modernization, as younger generations increasingly overlook the mathematical dimensions of their heritage. The research aims to reveal and interpret the mathematical structures inherent in these practices, which are often perceived merely as ritualistic or mystical. Employing a qualitative ethnographic approach, data were collected through participant observation, in-depth interviews with cultural leaders and community members, and supporting documentation. The findings demonstrate that the tradition involves sophisticated mathematical operations, including addition, division, modular arithmetic, and logical reasoning, systematically applied in the calculation of auspicious dates based on the local calendar system. The study further models these cultural practices as structured mathematical knowledge, illustrating their potential integration into contextual mathematics education. The results highlight the dual function of this tradition: as a medium for cultural preservation and as a rich source for innovative mathematics learning. This research underscores the importance of safeguarding local wisdom by documenting and incorporating ethnomathematical practices into educational curricula, thereby fostering cultural appreciation and mathematical understanding among the younger generation.