It is widely recognized that flipped learning has great potential for enhancing students' conceptual understanding through the reversed arrangement of before-class learning activities and in-class settings. However, this approach also raises the challenge of students having to obtain the learning content by themselves, especially for abstract concepts such as fractions, where students frequently encounter problems in mathematics education. In this study, we proposed a gamified interactive e-book approach to supporting a flipped mathematics classroom. To evaluate the effectiveness of the proposed approach, a quasi-experimental study was implemented in an elementary school mathematics course. There were three groups: the students who adopted the gamified interactive e-book in the mathematical flipped classroom (the GIEBFL group), the students who learned with conventional flipped learning (the CFL group), and those who learned with traditional instruction (the TI group). The results from a paper-and-pencil test indicated that the GIEBFL students significantly outperformed the CFL and TI students. In addition, the questionnaire of students' learning motivation showed that the GIEBFL students had better motivation than the CFL and TI students. Also, the GIEBFL students achieved significantly higher meta-cognition tendency than the TI students.