Salsabila, Zahrina, and Dian Permatasari. “Single Subject Research: Can a Contextual Approach to Ratio Material Facilitate Understanding of Concepts for Mentally Retarded Students?”. 12 Waiheru 10, no. 1 (June 1, 2024): 28–41. Accessed April 3, 2025. https://12waiheru.kemenag.go.id/index.php/journal/article/view/200.