Many people do not realize that all activities carried out have cultural and mathematical values. This research was conducted in four villages in the Montasik sub-district, Aceh Besar district. The purpose of this study was to determine the traditional calculations, mathematical fundamental activities contained in the activities of rice farmers and agricultural activities that can be designed in making math story problems in junior high school. This study uses qualitative research with an ethnographic approach. The research subjects were rice farmers in four villages in Montasik District, Aceh Besar District, namely Weu Krueng Village, Alue Village, Warabo Village and Seumet Village. Using purposive sampling technique. The researcher selected 2-3 informants from each of the four villages who met the criteria to be studied. The data collection methods used were interviews and documentation. The results showed that there were traditional calculations and four fundamental activities in the activities of rice farmers. These activities are counting, placing, measuring, and designing. The most frequently used activities are counting and measuring. Farmers carry out each activity with calculations such as calculating how many seeds are needed for a 1 hectare rice field. The activity of measuring in the activities of rice farmers such as measuring the area of rice fields and the distance in planting rice. These activities can be designed into several math problems in junior high school.