This study aims to examine the effect of using colored number card media on the mathematics learning outcomes of first-grade students at SD Negeri Pao-Pao, particularly in addition material. The research employed a quantitative approach with a pre-experimental method using a One Group Pretest–Posttest design. The population consisted of all first-grade students of SD Negeri Pao-Pao, who were also used as the research sample, totaling 24 students. The research instruments included learning outcome tests in the form of pretest and posttest on addition material, while data were collected through tests administered before and after the treatment. The obtained data were analyzed using descriptive and inferential statistical analysis to determine the effect of implementing colored number card media on students’ mathematics learning outcomes. The findings show that the use of colored number card media significantly improved students’ mathematics learning outcomes. Initially, the average pretest score was 51.67, and most students (95.83%) had not met the Minimum Mastery Criteria (KKM). After the learning process was conducted using the colored number card media for three meetings, the average posttest score increased to 89.17, and all students achieved learning mastery. This result was further supported by the paired samples t-test, which showed a significance value of 0.000, lower than 0.05, indicating a significant difference between students’ learning outcomes before and after the implementation of the learning media.