<![CDATA[This study aimed to determine the effectiveness of a simulation-based Project-Based Learning (PjBL) model in improving the critical thinking skills of fifth-grade students at SD Muhammadiyah Kranggan on fraction topics. The research employed a mixed-methods approach with a sequential explanatory design. The quantitative phase used a one-group pretest-posttest design involving nine students as research participants. Research instruments included a critical thinking skills test, observation sheets, and interviews with teachers and students. Quantitative data were analyzed using a paired sample t-test, while qualitative data were analyzed through data reduction, data display, and conclusion drawing. The results revealed that the students' mean pretest score of 45.56 increased to 82.22 in the posttest, representing an improvement of 36.66 points. The paired sample t-test yielded a significance value of 0.000 (p < 0.05), indicating a significant difference in critical thinking skills before and after the implementation of the learning model. Observation results showed increased student participation, collaboration, and engagement during the learning process. Interview findings further indicated that simulation activities helped students understand fraction concepts more concretely and enhanced their learning motivation. Therefore, the simulation-based Project-Based Learning model was proven effective in improving elementary school students' critical thinking skills.]]>
