Contextualizing Mathematics in Tugu Yogyakarta: A Case Study on Students' Numerical and Visual Estimation Skills

This research explores the impact of ethno-RME on students' thinking processes in solving decimal number operations in Tugu Yogyakarta, Indonesia. The study involved 32 grade 4 students and used three data collection techniques: task provision, cognitive interviews, and documentation. The qualitative data was analyzed using cross-sectional data and focus group discussions (FGD). The study results show that students' thinking process for completing ethno-RME-based mathematics tasks can be divided into two strategies. The first strategy is numerical estimation, where students who use this strategy focus on the numerical information available in each problem. The second strategy is visual estimation, where students who use this strategy focus on constructing a flat shape as closely as possible to the actual shape of the Tugu Yogyakarta. There is a rich context of sociocultural values that can be used to build students' character and ethics when utilizing science, especially mathematics.