The research aimed to achieve the following objectives: 1)Assess the effectiveness of cooperative learning management utilizing the STAD technique and KWDL technique among PrathomSuksa 6 students in solving decimal problems, with a target of achieving a 75/75 criterion, 2) Enhance the problem-solving abilities of grade 6 students in mathematics by implementing cooperative learning management using the combined STAD technique and KWDL technique, compared to a 75 percent criterion, 3) Improve the learning achievement in mathematics of grade 6 students in solving decimal problems through cooperative learning management, employing the STAD technique and KWDL technique, in line with a 75 percent criterion. The research was conducted with a selected group of 33 students from Prathomsuksa 6/1, first semester, academic year 2022, at Ban Chiang Yuen School. The research tools employed were: 1) a cooperative learning plan incorporating the STAD and KWDL techniques, 2) a mathematics problem-solving ability test, and 3) a mathematics learning achievement test. Data analysis involved the use of percentage, mean, standard deviation, and efficiency (E1/E2). The findings of the study indicated the following: Cooperative learning management using the STAD technique and KWDL technique exhibited an efficiency of 76.14/75.45, satisfying the 75/75 criterion. The average mathematics score post-intervention was 75.76 percent, surpassing the 75 percent criterion. Mathematics learning achievement, as measured by the average score post-intervention, reached 75.45 percent, fulfilling the 75 percent criterion.