Best maths app ever. My 4 year old is so addictive to it. Hope the new multiplication/division app comes out soon since he unlocked most of the worlds already. There is one problem though. Some of the exchanges (the one where the guy exchange you diamond to unlock a new world, and the one where they exchange ice cream/cup cake for coins) has really bad graphic. We cannot see how many items to exchange for how many coins. It would be great if you fix that