Hypothetical Learning Trajectory in STEM Approach with Project-Based Learning Model to Improve Students' Mathematical Proficiency

The aims of this study were to desribe the design of teaching and learning process of Science, Technology, Engineering, and Mathematics (STEM) approach with the Project-Based Learning (PjBL) model in improving students' mathematical proficiency on linear equations in one variable topic. This research uses design research methods with steps, namely a preliminary design, teaching experimental, and retrospective analysis. The data were obtained from 50 junior high school students in grade VII in student worksheets, observation sheets during research, mathematical proficiency test instrument in the form of essay that has been through expert, the result of the interview, documentation, and video recording. The research results showed that: (1) HLT in STEM approach with the PjBL model has an effect of developing students' mathematical proficiency; (2) the mathematical proficiency of junior high school students were in a high category with n-gain 0.79. The results of this study can be used as a basis for designing a local instruction theory linear equation in one variable on STEM approach with the PjBL model to develop junior high school student students' mathematical proficiency.