Interdisciplinary teaching is a curriculum approach that integrates two to more subject areas into a meaningful association in order to enhance and enrich students learning in each subject area. This study aimed at exploring how second-grade students' understanding of integrating mathematics concepts with movement were evolved and enhanced by the teacher's task design and instructional strategies through creating games in an integrated unit. One physical education teacher, one second-grade classroom teacher, and 22 second-grade students voluntarily participated in this study. Data were collected through (a) conducting one formal interview with the two teachers, respectively, and five group-interviews with the students; (b) videotaping the teachers' teaching six integrated lesson to the second grade students, (c) completing descriptive statement about observation of the teachers' teaching and the students' learning responses, and (d) collecting the teacher's lesson plans and the students' task sheets and journal entries. The investigators independently analyzed the data using the constant comparison technique. The interview transcripts were sent to the teachers for member checking. Analysis of the data yielded three themes: (a) Engaging students' previous knowledge in designing coherently integrated games. The teacher's incorporating the students' prior knowledge and ideas into the process of creating games and providing students with specific guidelines elicited and promoted the students to create their own games that coherently integrated mathematics concepts and movements. For example, group A created a game named Extreme Bowling that combined addition, subtraction, doubles, areas, kickboxing, underhand throwing, bowling together; (b) Facilitating students' elaboration on and refinement of the integrated games. As a result of the teachers' encouraging the students to make necessary changes about their own games, each group redesigned the games by redefining game plays, adding and deleting some equipment, re-setting the equipment up, and clarifying game rules; (c) Involving community of learning in the process of creating games. The teacher' offering collaborative learning opportunities, presenting norms for cooperative group work, and providing on-going suggestions if necessary facilitated the students to demonstrate cooperative skills while creating games. For example, the students discussed and negotiated about what mathematics concepts and movements should be included in their games, shared ideas with group members about how to play the game, listened to group members' ideas, and shared responsibilities for setting up their games. This study suggested that students could design interestingly integrated games when they were provided with integrated learning experiences and appropriate instructional guidance.Keyword(s): creative movement, interdisciplinary, research