<![CDATA[This study was motivated by the observation that mathematics instruction for fifth-grade students at SDN Pandansari 01 and SDN Pandansari 02 tended to be teacher-centered, with suboptimal use of instructional models and media. The study aimed to determine the differences in and improvements to students' critical thinking skills through the use of the Problem-Based Learning model supported by flashcard media. A quantitative approach was employed using a quasi-experimental design—specifically, the Nonequivalent Control Group Design. The study population consisted of 76 students, with a sample of 58 students divided into an experimental class (29 students) and a control class (29 students). Data were collected through interviews, observations, tests, and documentation. Data analysis was conducted using the Independent Sample t-test, Paired Sample t-test, and N-Gain analysis with the aid of SPSS 25 software. The results revealed a difference in critical thinking skills between the experimental and control classes, with a significance level of 0.011 (p < 0.05). The mean post-test score for the experimental class was 67.21, which was higher than that of the control class (55.97). The Paired Sample t-test indicated a significant improvement in the experimental class, with p < 0.001. The mean N-Gain percentages were 53.01% for the experimental class and 32.14% for the control class; both fell within the "medium" category. Thus, the Problem-Based Learning model supported by flashcards is effective in enhancing students' critical thinking skills regarding the topics of pictograms and bar charts.]]>
