M. Farida, H. Sihotang, and C. Ditasona, “ANALYSIS OF STUDENTS’ DIFFICULTIES IN SOLVING ALGEBRAIC OPERATION PROBLEMS BASED ON PROBLEM-SOLVING SKILLS IN GRADE VII AT SMP NEGERI 8 TAMBUN SELATAN”, EduMatSains, vol. 8, no. 2, pp. 228-238, Feb. 2024.