In various cultural activities, there is mathematics known as ethnomathematics. The purpose of this study is to identify and describe mathematical activities in the barter culture in the Geliting Maumere market. Geliting market is one of the traditional market in Kewapante sub-district, Sikka Regency, East Nusa Tenggara Province. This research is a qualitative research using an ethnographic research design. The informants in this study were five people aged 61-77 years. Data were collected by means of interviews, observation, and documentation. Data validation was done by source triangulation method. The data were analysed using ethnomathematical characteristics referring to the Miles and Huberman model. The results showed that there was a mathematical activity known as ethnomathematics in barter culture. Estimating the price of merchandise to be exchanged for other merchandise. Compare the prices of the items to be exchanged. School mathematics concepts related to ethnomathematics in barter cultural include: linear equation of two variables, mathematical logic, addition, subtraction, multiplication, division, and social arithmetic. Developed teaching materials for learning the school’s mathematical concepts. Teaching materials with cultural context as a new innovation in learning mathematics in schools. So that learning will be more fun.

Keywords: activities, barter, culture, ethnomathematics, mathematics learning