Learn the basics and become faster at mental arithmetic!
In the game 1x1 you can practice the basics. If you are in the
given time on solfing ten invoices correctly, you move up a level.
At each stage change you may choose a sticker to stick on your
personal stickers Wall.
In Game Center you can challenge your friends and challenge them.
* 50 Levels
* Over 60 Different Stickers
* Game Center Achievements