Practising arithmetic through a race

Lay the phone between two players; the screen is split and the top half is rotated for the second player. Both see the same question with a few answer choices. The first to tap the right answer scores, while a wrong answer locks that player for one second, so random guessing does not pay. Easy has small additions and subtractions; medium and hard add multiplication and division. The fastest win per level is saved on your device.