Acquiring simple arithmetic skills at the preschool level requires repetitive practices. One method for encouraging students to spend longer time practicing is by presenting the skills in an engaging game. As student retention on the game increases, the student will be more likely to acquire the practiced skill since she will have spent more time practicing. In this paper, we examine the relationship between internal locus of control and retention in game-based learning applications for young children using Todo Math, a mobile-based math learning application for children from Pre-K to 2nd grade. We examine 345,783 users' log data to show that when children prefer "free" mode, which has high internal locus of control, their retention on Todo Math is higher than children who prefer "daily" mode, which has high external locus of control. We present three analyses that support our findings using survival analysis, post-hoc analysis, and t-test.