Kanjana Ninnuan and Montree Wongsaphan 2024. Implementation of the Learning Management Model Based on Cognitive Development Theory to Enhance Mathematical Problem-Solving Ability for Prathomsuksa 6 Students. Journal of Educational Issues. 8, 2 (Jun. 2024), pp. 58–71. DOI:https://doi.org/10.5296/jei.v8i2.19963.