In this paper, we present a methodology for learning elementary-school mathematics online. It is supported by a decision making system, based on evolutionary computation, which leads a student in selecting an optimal subset of math items to effectively upgrade the knowledge. We evaluated the system’s effectiveness with the active participation of experienced teachers and students. The teachers evaluated solutions provided by the systems, judging the selection with respect to content areas and difficulty levels. The students were solving math items suggested by the system, gradually improving their knowledge. They both agreed that the system could effectively be used for e-learning.