Rajagukguk, Waminton. “DEVELOPING MATHEMATICAL PROBLEM SOLVING SKILLS WITH INTERACTIVE PROBLEM BASED LEARNING AND DISCOVERY LEARNING”. JURNAL HANDAYANI PGSD FIP UNIMED 11, no. 1 (June 23, 2020): 29–41. Accessed January 31, 2025. http://103.242.233.34/index.php/handayani/article/view/18657.