This paper presents an overview of some educational problems that are, mathematically modeled, recognized as NP-hard. In addition to the well-known problems related to the scheduling of classes, courses and exams, some others have become interested with e-learning. In this context, problems related to the composition of optimal personalized e-courses, curriculum development in such a system, and curriculum organization in general are discussed. When designing curricula and choosing an optimal teaching and learning strategy, there are some problems that can be seen as NP-hard. A possible solution is illustrated by an example of small dimensions.