I have bought a tablet for a 5 year old. I'm struggling to find games that would be appropraite for her and a 2 year old. 

It's a generic tablet running an android os.

The 5 year old starts school next year.  

I would like some educational games that will help her with numbers, colours, letters etc, but also some fun games. Her mum doesn't have a tablet or computer so the kids haven't really been exposed to this technology.

Any suggestions on what would Ikeep a toddler and preschooler amused ?