iPhone math app

Can anyone recommend an app for my iPhone that is a math game or even just math facts?  I do not use flash cards, but my daughter does like to drill when we are waiting in line, etc.  I like to do it with her verbally, but sometimes we have to be quiet or I cannot interact.  It would be nice to have an app that at least she is learning something instead of just playing a game. 

Any other recommendations for games (girls ages 3 & 6) where they learn something would be appreciated too.

Crystal