Ningsih Sagala, Prihatin, Pristi Suhendro L, and Eri Widyastuti. 2022. “Development Of First High School Mathematics LKPD Based On Case Method Integrated Local Culture Mandailing Tribe”. International Journal of Educational Research &Amp; Social Sciences 3 (4):1734-43. https://doi.org/10.51601/ijersc.v3i4.463.