Woranetsudathip, Naphaporn. “Examine First Grade Students’ Strategies of Solving Open-Ended Problems on Addition”. Asia Research Network Journal of Education 1, no. 1 (April 30, 2021): 15–24. Accessed May 19, 2024. https://so05.tci-thaijo.org/index.php/arnje/article/view/250020.