<![CDATA[This study aims to develop educational materials rooted in Central Javanese culture and based on indigenous mathematics, with a view to stimulating students’ interest in learning and fostering their higher-order thinking skills. This study adopts a research and development method based on the Borg and Gall model, modified into eight stages: identification of potential issues, data collection, product design, design validation, design revision, product trialing, product revision, and user trialing. The research utilized a two-group pretest-posttest design comparing a control class and an experimental class. Data analysis techniques included the paired-sample t-test, independent-sample t-test, and N-gain analysis. Several experts conducted product validation. The validation results from the content expert yielded a score of 95.83% (highly acceptable), the media expert scored 93.75% (highly acceptable), and the language expert scored 94.79% (highly acceptable). The practicality test of the teaching materials among students yielded a score of 98.3% in the control group and 99.2% in the experimental group, indicating high practicality. Meanwhile, the practicality test by teachers in the control group and the experimental class each yielded a score of’100%, indicating high practicality. The independent sample t-test showed a statistically significant difference in student’s learning interest between the experimental and control groups (sig < 0,05), with N-Gain score of 0,60 for experimental group and 0,38 for control group. Similarly, a statistically significant difference was found in students’ higher-order thinking skills between the two groups (sig < 0,05), with n-Gain scores of 0,61 for experimental group and 0,38 for the control group. This study demonstrates that applying ethnomathematics-assisted learning to the multiplication and division of decimal numbers can enhance interest in learning and higher-order thinking skills. This study concludes that the developed teaching materials meet high standards in both effectiveness and practicality, making them a viable option for mathematics instruction at the elementary school level.]]>
