The use of modulo in wedding party: An ethnomathematical study in Kampung Kuta

It is undeniable that mathematical concepts are integrated with cultural ideas and values ​​in everyday life. This article explores the first area, namely basic field data collection, which was conducted to investigate the application of mathematical concepts in cultural ideas and activities, particularly in determining the appropriate time for a wedding reception. This study aims to explore forms of ethnomathematics in everyday life, ideas, and activities. Therefore, this study seeks to explore mathematical concepts in the activity of determining time, which is considered to bring good luck and taboo in wedding ceremonies that are suspected to involve mathematical concepts (such as number patterns, calendar systems, time cycle calculations, or probability principles) so that they can be solved with simpler methods. This study uses an ethnomethodological approach operationalised in a realist ethnographic design. Data collection was conducted through participant observation and in-depth interviews with the community and traditional elders in Kampung Kuta. The study results show that the Kampung Kuta community use a number system to determine the appropriate time for wedding ceremonies, based on the values ​​of the Saptawara and Pancawara periods. Furthermore, the mathematical concept used in this number system is the modulo n congruence.