Rojsiraphisal, Pontip. “Factors Effecting Difficulties in Learning Mathematics of Students in Primary and Upper Secondary Education Level”. Journal of Education Yala Rajabhat University 3, no. 1 (June 29, 2024): 80–90. accessed September 11, 2026. https://so08.tci-thaijo.org/index.php/jeduyru/article/view/2667.