PHOMMANITH , K., OUNKEO, C., BOUSITH , O. and KEOPHASITH, V. (2021) “A Study Mathematics Achievement by Using Problem-Based Learning for Grade 1 Students”, Souphanouvong University Journal Multidisciplinary Research and Development , 7(1), pp. 70–78. Available at: http://www.su-journal.com/index.php/su/article/view/98 (Accessed: 17 January 2026).