Sitorus, J. J. B.; Suweken, G. .; Ardana, I. M. . Pengaruh Model Pembelajaran Problem Based Learning Dengan Pendekatan Difrensiasi Terhadap Kemampuan Pemecahan Masalah Matematika Siswa SMP Kelas VII Pada Materi Perbandingan: The Influence of the Problem-Based Learning Model With a Differentiated Approach on the Mathematical Problem-Solving Ability of Seventh-Grade Junior High School Students in Proportions. CITIZ. J. Ilm. Multidiscip. Ind 2026, 6, 602-611.