Font Size: 

Ethnomathematics studies mathematical aspects found in a particular culture. The result of the study is important in mathematics education. The student can learn mathematical concepts through cultural activities that are familiar to them. Furthermore, ethnomathematics contributes to the effort of preserving culture in a society. This study aims to know mathematical aspects in one of cultural activity, namely Grubregan in Baran Wetan village, Rongkop, Gunungkidul. The study was done based on six mathematical fundamental activities according to Bishop, namely counting, measuring, locating, designing, playing, and explaining. This is a qualitative descriptive research. The data were collected using interview and observation. The study found that determining the amount of sesaji dan the day or date for the Gumbregan are a counting activities. Measuring the dimension of the ketupat can be considered as a measuring activity. Determining the location for the activity is a locating activity. Designing activities can be found in the designing of ketupat and jadah. Rules and reasoning of the Gumbregan can be considered as playing and explaining activities. This study also developed some mathematics problem related to Gumbregan for elementary students.

ethnomathematics, six mathematical fundamental activities, Gumbregan