This study explored the effectiveness of incorporating board games into the teaching of “Addition and Subtraction” unit in second-grade remedial mathematics instruction. Employing the action research method, five second-grade students were selected as the participants, and three unit courses were designed: “Addition and Subtraction of Two-Digit Numbers”, “Application of Addition and Subtraction”, and “Two Steps of Addition and Subtraction”. The teaching was conducted over two cycles from November 2019 to December 2019, using the board games “Poker 99”, “You Add and I Subtract”, and “The Biggest Number is the King” as instructional aids. Data were collected from classroom observations, interviews, worksheets, pre- and post-test papers, and reflection notes. The analysis results indicate that 1. hoosing an appropriate board game based on mathematical concepts enhances students’ mathematics abilities; 2. adjusting the difficulty and rules of board games helps maintaining students’ motivation in learning; 3. board games facilitate the establishment of mathematical concepts of addition and subtraction, and improve basic computation skills.