Thuaithong P, Sumirattana S, Yamrung R. THE EFFECT OF USING MULTIPLE REPRESENTATIONS LEARNING ACTIVITY ON MATHEMATICS PROBLEM SOLVING ABILITY IN SYSTEM OF EQUATIONS WITH TWO VARIABLES OF MATHAYOMSUKSA III STUDENTS. JMND [internet]. 2024 Apr. 30 [cited 2025 Dec. 10];11(4):199-20. available from: https://so03.tci-thaijo.org/index.php/JMND/article/view/276647