มะหาทอง แก้วอุดอน, and พรประไพ ศศิวิมล. “Mathematical Learning Activities on the Topic of Fraction by Using the Multigrade Classroom Learning Activities in the Primary Education Level”. Journal of Graduate School, Pitchayatat, Ubon Ratchathani Rajabhat University 14, no. 1 (October 16, 2019): 7–12. Accessed May 17, 2024. https://so02.tci-thaijo.org/index.php/Pitchayatat/article/view/221551.