This study aimed to improve the numerical ability of first-grade elementary school students through the use of play money as a learning medium in mathematics. This research employed classroom action research conducted in two cycles, each consisting of planning, implementation, observation, and reflection stages. The subjects of the study were 12 first-grade students. Data were collected through tests and observations. The results showed that the use of play money as a learning medium improved students’ numerical abilities, particularly in number recognition and simple addition and subtraction operations. The improvement was reflected in the increase in the students’ average scores from 60 in the initial condition to 70 in the first cycle, and further to 80 in the second cycle. In addition, student participation and engagement in the learning process also increased. It can be concluded that the use of play money is effective in improving the numerical ability of first-grade elementary school students. Keywords: Numerical ability, play money, mathematics, first-grade students, learning media