When performing a task in the classroom, it is essential to place the focus on learning. In the classroom, it is possible to distinguish between time spent by students on-task and off-task. The former is the time in which the student is focused on the learning task; the latter is the remaining time in which they focus on other activities. Understanding the relationship between the two is a concern for teachers, especially for those who teach mathematics and other subjects that are often considered unattractive by students. Given the opportunity afforded by educational video games to motivate and engage math students, an educational drill-and-practice video game was used in this study to practice second-grade arithmetic and study the students' on-task and off-task behavior. We found that when practicing arithmetic using an educational drill-and-practice video game, time on-task decreases during an activity (30 minutes) as well as over the course of the school year (March to December). This study has implications for the length of mathematics classes at schools as well as the need to vary activities during a class.