<![CDATA[This study was designed to investigate the enhancement of students' critical thinking capacities by implementing a Problem-Based Learning (PBL) model integrated with the Science, Technology, Engineering, and Mathematics (STEM) approach to polynomial division topics at the high school level. A quantitative method utilizing a Pre-Experimental One-Group Pretest–Posttest Design was managed in this framework. Through a purposive sampling technique, 14 students from class XI-1 at GKPI Padang Bulan Private Senior High School were determined as the research participants. The research data were gathered using critical thinking competency tests distributed prior to and following the learning intervention, which were subsequently computed through the N-Gain analysis. The empirical evidence indicated a noticeable shift in the students' performance, where the average pretest score of 52.14 substantially expanded to 76.43 during the posttest. Furthermore, the N-Gain computation demonstrated a mean score of 0.50, which falls into the moderate growth classification. This intellectual growth was visibly observed across several key parameters, including analysis, evaluation, inference, and the formulation of problem-solving pathways. These outcomes emphasize that combining the Problem-Based Learning framework with a STEM orientation successfully establishes a student-centered, active, and contextual learning environment that effectively drives critical reasoning within mathematics pedagogy. Consequently, STEM-driven Problem-Based Learning represents a promising instructional strategy to elevate high school students' critical thinking attributes regarding polynomial division materials. ABSTRAK Penelitian ini ditujukan guna menguji eskalasi kecakapan berpikir kritis peserta didik lewat implementasi model Problem-Based Learning (PBL) yang diintegrasikan dengan pendekatan Science, Technology, Engineering, and Mathematics (STEM) pada topik pembagian suku banyak di jenjang SMA. Pendekatan kuantitatif dengan rancangan Pre-Experimental tipe One Group Pretest–Posttest diterapkan dalam riset ini. Penentuan subjek riset menggunakan teknik purposive sampling, yang menghasilkan sampel sebanyak 14 siswa kelas XI-1 SMA Swasta GKPI Padang Bulan. Pengumpulan data kuantitatif dilakukan melalui instrumen tes kemampuan berpikir kritis yang diselenggarakan pada fase sebelum (pretest) dan sesudah (posttest) intervensi pembelajaran, di mana data yang diperoleh kemudian diolah menggunakan uji Normalized Gain (N-Gain). Hasil eksperimen memperlihatkan adanya pergeseran positif pada rerata skor siswa, dari yang semula sebesar 52,14 pada saat pretest melonjak menjadi 76,43 ketika posttest. Berdasarkan kalkulasi uji N-Gain, didapatkan nilai rata-rata sebesar 0,50 yang merepresentasikan tingkat peningkatan pada kategori sedang. Perkembangan kecakapan berpikir kritis ini teridentifikasi secara konkret pada indikator analisis, evaluasi, inferensi, serta keterampilan mendesain strategi penyelesaian masalah. Output riset ini mengonfirmasi bahwa perpaduan model Problem-Based Learning berorientasi STEM sukses menstimulasi lingkungan belajar yang interaktif, kontekstual, serta berorientasi pada kemandirian siswa (student-centered), sehingga berkontribusi nyata terhadap stimulasi nalar kritis dalam kurikulum matematika. Oleh karena itu, penerapan PBL berbasis STEM layak direkomendasikan sebagai salah satu opsi strategi instruksional yang andal demi memacu kemampuan berpikir kritis siswa SMA pada materi pembagian suku banyak.]]>
