PENGARUH PENDEKATAN PROBLEM BASED LEARNING BERBANTUAN MASALAH OPEN-ENDED TERHADAP KEMAMPUAN BERPIKIR KRITIS DITINJAU DARI SIKAP MATEMATIS SISWA [THE INFLUENCE OF THE PROBLEM-BASED LEARNING MODEL ASSISTED BY OPEN-ENDED PROBLEMS TOWARDS MATHEMATICAL CRITICAL THINKING SKILLS BASED ON STUDENTS' MATHEMATICAL ATTITUDE]
JOHME: Journal of Holistic Mathematics Education