23 Points is a reaction math game, curious?
Get it for free, train your brain.

iTunes: https://itunes.apple.com/app/23-points/id918952924?mt=8
Google Play Store: https://play.google.com/store/apps/details?id=davidzobrist.twentythree
Amazon Store: http://www.amazon.de/David-Zobrist-23-Points/dp/B00OIZXSS4/