“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) 7, no. 06 (June 4, 2019): 144–165. Accessed May 5, 2024. https://ijsrm.net/index.php/ijsrm/article/view/2175.