Nasution RW. MENINGKATKAN HASIL BELAJAR MATEMATIKA SISWA MELALUI METODE PROBLEM BASED INSTRUCTION DI KELAS VI SD NEGERI NO. 020 BONANDOLOK. JH [Internet]. 2016 Dec. 19 [cited 2025 Jan. 31];6(1). Available from: http://103.242.233.34/index.php/handayani/article/view/5045