<![CDATA[This study is motivated by the low critical thinking, collaboration, and communication skills of Grade I students at SDN Antasan Kecil Timur 1 in Mathematics learning on the topic of Numbers 11–20, characterized by passive student dominance and suboptimal group cooperation. This study aims to describe teacher and student activities and analyze the improvement of critical thinking, collaboration, communication skills, and learning outcomes through the PRO-BINTANG model (Problem Based Learning, Numbered Heads Together, and Talking Chips). This research employs a qualitative descriptive approach with a Classroom Action Research (CAR) design conducted over four meetings through the stages of planning, action, observation, and reflection. Subjects were 20 Grade I students (11 boys and 9 girls) in the 2025/2026 academic year. Data were collected through observation and tests, analyzed descriptively and through cross-tabulation. The results show that teacher activity reached the success indicator with a "Very Good" criterion, while student activity reached the success indicator with "Almost All Students Very Active." Students' critical thinking, collaboration, and communication skills each reached the success indicator with an "Almost All Students Very Skilled" criterion. Learning outcomes also reached the success indicators: affective outcomes with an "Almost All Students Behaved Very Well" criterion, psychomotor outcomes with an "Almost All Students Very Skilled" criterion, and cognitive outcomes showing consistent improvement across meetings until reaching the minimum completeness criteria (KKTP ≥65) with a "Complete (Tuntas)" criterion. These findings indicate that the implementation of the PRO-BINTANG model was associated with improvements in critical thinking, collaboration, communication skills, and learning outcomes of Grade I students in Mathematics]]>
