Analyzing Difficulties in Problem Solving of the Polygon Area for Elementary Students. Indonesian Research Journal in Education |IRJE|, [S. l.], v. 3, n. 2, p. 434–441, 2019. DOI: 10.22437/irje.v3i2.8436. Disponível em: https://www.online-journal.unja.ac.id/irje/article/view/8436. Acesso em: 17 apr. 2026.