Peningkatan Hasil Belajar Penjumlahan dan Pengurangan Kelas 2 SD Negeri Sawah Besar 01 melalui Problem Based Learning Berbantuan Media Kongkret. psnppg. 2023;1(2):2525-2533. Accessed August 12, 2026. https://conference.upgris.ac.id/index.php/psnppg/article/view/5409