Harahap NH, Lubis MS. Development of Student Worksheets (LKPD) on Integer Topics to Improve Seventh-Grade Students’ Mathematical Problem Solving Abilities at SMP Negeri 3 Halongonan. Mathline [Internet]. 2026 Feb. 24 [cited 2026 Feb. 25];11(1):91-106. Available from: http://mathline.unwir.ac.id/index.php/Mathline/article/view/1105