<![CDATA[This study aims to improve the procedural ability and mathematical critical thinking ability of fifth-grade students at SD Negeri Tamanan through the implementation of the Teams Games Tournament (TGT) cooperative learning model. This research was motivated by initial observations indicating low procedural and critical thinking abilities in whole-number arithmetic operations up to 100,000; for procedural ability, only 3 of 27 students (11%) reached the Learning Objective Achievement Criteria (KKTP) of 85 at baseline (pre-cycle diagnostic test), with a class average score of 44.1, while the mean critical thinking score at baseline was 41.9. This study is a Classroom Action Research (CAR) referring to the Kemmis and McTaggart model, conducted in two cycles with 27 students as subjects. Data were collected through tests and observations, then analyzed descriptively using quantitative and qualitative approaches. The results showed that the implementation of TGT through a series of activities—Soal Bergandengan, Hidden Math, Audiovisual Story Problems, Math Puzzle, and Flip Bottle Mario Challenge—was followed by an improvement in both abilities under study. The classical mastery of procedural ability increased from 29.6% in Cycle I to 55.6% in Cycle II, while the percentage of students in the Good or Very Good category for critical thinking ability increased from 44.4% to 100%. Both abilities improved descriptively, but after two cycles only the success indicator for critical thinking ability was achieved, while the indicator for procedural ability was not yet achieved, requiring further follow-up.]]>
