The only gripe I have is that they say the kids are using the apps for 30 minutes every day, for six weeks (presumably, that's 5630minutes, not 7630) -- but I don't know how much math kids that age get in school? Is it 45 minutes a day? Every other day?
Thanks for pointing it out (for posterity, and new users) -- I really do know better, but I always forget, whenever I try to write some math in-line in a comment... now the edit-window for parent was closed.