Cognitive ability is a crucial aspect of children's development that must be nurtured to prepare them for the next stage of education. This research aimed to develop children's cognitive abilities using number balls. The research employed a Classroom Action Research (CAR) approach, which was conducted in two cycles. Each cycle comprised planning, implementation, observation, and reflection. The research subjects were 20 children in Group B, while the research object was the cognitive abilities of early childhood children. The data was collected through observation, interviews, and document analysis to assess the improvement in cognitive abilities. The research findings indicate that children's cognitive abilities have developed very well. This is evident from the initial cognitive abilities of the children. Out of the 20 children in Group B, 1 child (5%) was categorized as "Not Developing Yet", 7 children (35%) were categorized as "Starting to Develop", 6 children (30%) were categorized as "Developing as Expected", and 6 children (30%) were categorized as "Developing Very Well". In Cycle II, there were no children (0%) in the "Not Developing Yet" category, 4 children (20%) in the "Starting to Develop" category, 6 children (30%) in the "Developing as Expected" category, and 10 children (50%) in the "Developing Very Well" category. The attainment of the development category was well achieved.