Challenge Me Math Workout - Nintendo DS

I've been using this to sharpen my mental math during my commute, and the drills are surprisingly addictive for a DS game. The disc-only copy I got works perfectly and loads quickly.

I’ve been using this during my commute to keep my mental math sharp. The drills are well-paced and the touch controls make it easy to jump between problems. Only wish it had a few more game modes to keep things interesting.

The drills are good for quick sessions while waiting, though the disc-only format means no case to protect it. I like that I can choose different difficulty levels, keeps my brain sharp on the train.