An adaptive learning system is proposed that incorporates a Bayesian network to efficiently gauge learners' understanding at the course-unit level. Also, learners receive content that is adapted to their measured level of understanding. The system works on an iPad via the Edmodo platform. A field experiment using the system in an elementary school begins in September, 2014. In addition to the contents of this paper, reports on the field experiments and a demonstration will be given at the conference poster presentation. [For the full proceedings, see ED562096.]