The aim of this study is to propose educational policies because it is ethically impossible for school education to implement empirical and experimental studies. For this purpose, we employ agent-based simulation to model academic skills of students. In the simulation model, we utilize three kinds of learning models, informational approach model, learning by teaching model and motivation for learning model, from learning theory in the literature, and then investigate how many teachers should be allocated to each school in order to improve academic abilities of students. Our main finding is twofold: First, any staffing decreases the abilities of the top 10%. Second, in contrast, the increase of those of the bottom 10% may depend on the staffing and it is in proportion to the number of teachers in elementary schools.