Mathshop is an educational program that teaches mathematics to pre-school and school-aged children in Mongolia. The document discusses using Bayesian Knowledge Tracing (BKT) to model students' knowledge based on their use of the Mathshop program. BKT is shown to accurately model over 60,000 practice problems completed by 765 students on 275 math skills. The models are able to predict student performance and identify skills they have yet to master to aid improvement. Results demonstrate BKT is effective for evaluating student knowledge in Mathshop and helping teachers, parents and designers optimize the program.