In this study we examined the effectiveness of a mobile game called MathDash for improving computational fluency as compared to a conventional drill and practice approach with computerized multiple-choice test items. An optical brain imaging method called functional near-infrared spectroscopy (fNIR) was utilized to assess changes in neural activity in the prefrontal cortex to examine the impact of increased attentional and cognitive training with MathDash. Overall, our experiment with college students indicated that MathDash was equally effective in terms of improving computational fluency in comparison to the drill and practice approach, whereas the gaming group utilized their prefrontal resources in a more energy efficient way.