Application of The Problem-Based Learning Model to Improve Students’ Mathematical Problem-Solving Abilities in Elementary School. Riemann: Research of Mathematics and Mathematics Education, [S. l.], v. 7, n. 2, p. 131–138, 2025. DOI: 10.38114/reimann.v7i2.59. Disponível em: http://journal.sanagustin.ac.id/index.php/reimann/article/view/59.. Acesso em: 18 apr. 2026.