<![CDATA[Science learning in elementary schools is often conducted through conventional methods, which tend to make students passive and struggle to understand abstract concepts, including the topic of ratio and proportion. This study aims to improve students’ learning activities, motivation, and achievement through the implementation of the Problem Learning (PBL) model assisted by Discovery-Based Student Worksheets (LKPD Project) in Grade VI students of SD Negeri 018 Long Kali. The research employed a Classroom Action Research (CAR) design, carried out in two cycles, each consisting of planning, action implementation, observation, and reflection. The research subjects were 25 students (13 boys and 12 girls). The instruments used included teacher and student activity observation sheets, learning achievement tests (pre-test and post-test), student response questionnaires, and project documentation. The results showed that the implementation of the PjBL model by the teacher increased from 82% in cycle I to 95% in cycle II, while student activity improved from 75% to 90%. The students’ average learning score increased from 62.4 (pre-action) to 85.6 (cycle II), with a classical mastery level of 88%. Students’ responses to the learning process were also very positive, with an average score of 89.4% (very good category). The students were more active, independent, and able to discover the concepts of ratio and proportion through contextual project activities In conclusion, the implementation of the Problem based Learning (PBL) model assisted by Discovery-Based Student Worksheets is effective in improving students’ learning activity, motivation, and achievement in mathematics, particularly on the topic of ratio and proportion. This model is feasible to be applied as an innovative learning alternative supporting the implementation of the Merdeka Curriculum in elementary schools Keywords: Problem Based Learning, Discovery Worksheet (LKPD Project), Ratio and Proportion, Learning Achievement, Elementary Students.]]>
