ทองสรรค์ ต, ศิริวงศ์ พ, ไชยณรงค์ ป. A Development of Mathematics Problem – Solving Skill Packages on Permutation and Combination for Mathayom Suksa Five . ubonreseva [internet]. 2021 Aug. 27 [cited 2026 Oct. 3];3(2):97-102. available from: https://so06.tci-thaijo.org/index.php/ubonreseva/article/view/250953