Analysis of Epistemological Barriers in Students’ Problem-Solving of Basic Algebra in Junior High School through the Didactical Design Research (DDR) Approach. Riemann: Research of Mathematics and Mathematics Education, [S. l.], v. 7, n. 3, p. 296–306, 2025. DOI: 10.38114/riemann.v7i3.130. Disponível em: http://journal.sanagustin.ac.id/index.php/reimann/article/view/130.. Acesso em: 18 apr. 2026.