There are plenty of free piano apps for both iOS and Android, but most of them make use of an on-screen piano, and teach little, if anything, in the way of theory and practical piano skills. Apps such as these are best thought of as games  they're fun but don't actually translate to real-life musical knowledge.

All of our online piano games are totally free at GamePix! They are available to play anywhere on any online device with a web browser, so you don't even need to buy or download any extra software.