Chomjumjung, K., & Phardthaisong, P. (2022). The Development of Problem Solving Ability in Mathematics of Muthayomsuksa 3 Students by Using Open Approach. Journal of Roi Et Rajabhat University, 16(1), 106–116. Retrieved from https://so03.tci-thaijo.org/index.php/reru/article/view/246601