<![CDATA[This study was motivated by classroom observations and interviews with mathematics teachers at SMP Nahdlatul Ulama (NU) Simo (a private Junior High School), which revealed that students experienced difficulties in mathematical modelling, particularly in the topic of Two-Variable Linear Equation Systems (SPLDV). These challenges were associated with teacher-centered instruction and the limited use of learning media that engaged students. To address these issues, Problem-Based Learning (PBL) integrated with the scaffolding method and supported by equation board media was implemented. This study aimed to describe students’ mathematical modelling achievement, learning responses, and classroom participation after the implementation of the instructional approach. A descriptive quantitative method with a one-shot case study design, classified as a one-group posttest-only pre-experimental design, was employed and supported by classroom observations. The participants were 26 students of 8th grade at SMP NU Simo. Data were collected through mathematical modelling tests, student response questionnaires, and classroom observations. The data were analyzed descriptively using test scores, questionnaire percentages, and observation results to determine students’ achievement categories. The findings showed that students’ mathematical modelling ability was categorized as good, with an average score of 80. Student responses toward the learning process were classified as very good, with an average percentage of 89%, while classroom participation reached the good category, with an average percentage of 79%. These findings indicate that implementing PBL integrated with scaffolding and equation board media was associated with students’ mathematical modelling achievement, positive learning responses, and active classroom participation.]]>
