Boonwirat, A., & Seethong, P. (2022). The Development of an Enrichment Curriculum on Mathematics Problem Solving Skills using DAPIC Problem Solving Process for Sixth . Journal of Humanities and Social Sciences, Rajapruk University, 8(2), 465–480. Retrieved from https://so03.tci-thaijo.org/index.php/rpu/article/view/263001