This study addresses the low mathematical problem-solving competency among Indonesian students, as evidenced by the PISA 2018 results that showed 71% failed to meet the minimum mathematical competency level. This study aims to develop a problem-based learning (PBL) module for systems of equations and inequalities content to improve Phase E students' mathematical problem-solving abilities. Using the ADDIE (Analysis, Design, Development, Implementation, Evaluation) model, this study involved expert validation, a small group trial with 12 students, and field implementation using a posttest-only control group design with 24 students in the experimental group and 25 students in the control group. The results showed the module achieved excellent validity (3.63/4.00), high practicality (86.53% small group, 84.74% field trial), and was highly effective with a classical completeness score of 95% in the experimental class. The PBL-based module successfully integrated mathematical problem-solving skill indicators, improving student motivation and learning outcomes. Teachers should implement this module while emphasizing solution verification, and future research should explore the long-term impact and potential digital integration.
Suharnita et al. (2026) studied this question.