Sumalong, Olis, Supriyatman Supriyatman, and Jusman Mansyur. 2021. “The Problem Solving Ability in Vector Addition by Using Grid and Parallelogram”. Jurnal Riset Pendidikan MIPA 5 (2). Palu, Sulawesi Tengah - INDONESIA:75-80. https://doi.org/10.22487/j25490192.2021.v5.i2.pp75-80.