Uyen, B.P. , Tong, D.H. and Han, N.N. 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 (Aug. 2021), 568–587. DOI:https://doi.org/10.18488/journal.61.2021.93.568.587.