Using an Improvised Abacus to Assist Samproso M/A Junior High School Level One Pupils to Overcome the Problem of Place Value Concept in Mathematics. International Journal of Scientific Research and Management (IJSRM), [S. l.], v. 7, n. 06, p. 144–165, 2019. DOI: 10.18535/ijsrm/v7i6.m01. Disponível em: https://ijsrm.net/index.php/ijsrm/article/view/2175.. Acesso em: 5 may. 2024.