Mental arithmetic is a fundamental skill that should be developed from an early age because it contributes to children's calculation abilities, concentration, memory, and understanding of mathematical concepts. However, many children still experience difficulties in performing arithmetic operations quickly and accurately, indicating the need for engaging and effective learning methods. This community service program aimed to improve participants' understanding of the use of the abacus method as a learning strategy for developing children's mental arithmetic skills. The program was conducted as a workshop in Tanimulya Village involving children from kindergarten to third grade of elementary school. The activities consisted of preparation, material presentation, abacus demonstration, hands-on practice, guided assistance, and evaluation through pretests, posttests, and participant perception questionnaires. The results showed an improvement in participants' understanding of mental arithmetic concepts and abacus techniques. The evaluation also indicated that most participants perceived the abacus method as beneficial for improving calculation speed, accuracy in solving arithmetic operations, understanding of mathematical concepts, concentration, self-confidence, and mental arithmetic skills.