Harahap, N.H. and Lubis, M.S. 2026. Development of Student Worksheets (LKPD) on Integer Topics to Improve Seventh-Grade Students’ Mathematical Problem Solving Abilities at SMP Negeri 3 Halongonan. Mathline : Jurnal Matematika dan Pendidikan Matematika. 11, 1 (Feb. 2026), 91–106. DOI:https://doi.org/10.31943/mathline.v11i1.1105.