Marhamah Hasibuan, A., Fauzi and Ermawati 2025. Development of Differentiated Mathematics E-books Based on Langkat Malay Culture to Improve Students’ Functional Thinking and Critical Thinking Skills. Journal of Practice Learning and Educational Development . 5, 4 (Dec. 2025), 1268–1279. DOI:https://doi.org/10.58737/jpled.v5i4.878.