Abstract
Digital learning materials such as iterative learning have a high drop-out rate contrary to demand and lack support for the maintaining motivation of beginning students. The purpose of this study is to develop a serious game for learning that solves this problem. We created an algorithm for learning serious games that adjusts the difficulty level of the learning task for each learner based on flow theory. In this paper, we implement the proposed algorithm on Excel and describe its effectiveness based on the results obtained from 20 users.