This paper presents a novel algorithm for tagging the relationship of test on the learning content called Binary Union-plus Tag (BUT). The proposed algorithm is motivated by the desire of students to re-study unacquainted content after a test. By binary coding items of content, BUT provides the users of an e-Learning system a certain range of content which lacks learning to connect to tests and content. It starts off with one of the content structures as a reference structure. Then, all the mistakes made on the test are mapped to the reference structure to highlight the re-studying area in the learning materials. To evaluate the performance of the proposed method, it has been used on the learning process of two hundred grade students. Moreover, the experimental results show that the proposed algorithm can considerably improve the achievement of students in terms of both locating the essential range of the content and providing the necessary matters.