Phenglun, P., Khansila, P. and Nongharnpituk, P. 2023. Development of mathematics learning achievement on quadratic equations for Grade 9 students using STAD technique with the game. Kalasin University Journal of Humanities Social Sciences and Innovation. 2, 1 (Jun. 2023), 80–92. DOI:https://doi.org/10.14456/hsi.2023.7.