Problem-Based Learning Approach for Elementary Schools: A case study of five Years Compulsory Education system. Innovation Journal of Social Sciences and Economic Review, [S. l.], v. 3, n. 2, p. 11–17, 2021. DOI: 10.36923/ijsser.v3i2.69. Disponível em: https://mail.ijsser.com/index.php/ijsser/article/view/69. Acesso em: 2 jan. 2026.