Uyen, Bui Phuong, Duong Huu Tong, and Nguyen Ngoc Han. 2021. “Enhancing Problem-Solving Skills of 8th-Grade Students in Learning the First-Degree Equations in One Unknown”. International Journal of Education and Practice 9 (3):568-87. https://doi.org/10.18488/journal.61.2021.93.568.587.