Lakphet, Kanwara, Woranuch Yamsang, and Nopporn Yamsang. 2021. “Diagnosis of Mathematical Deficiencies in Fractions of Prathom Sueksa Five Students at a School in Cluster 32, Prawet District Office, Bangkok Metropolis”. Journal of the Association of Researchers 26 (1):393-411. https://so04.tci-thaijo.org/index.php/jar/article/view/250082.