Many countries spell it this way. There is absolutely nothing wrong with it. In fact, I think it makes more sense. In my mind, it makes more sense to shorten "mathematics" to "maths" rather than "math"
We do that too, in Australia. We start differentiation in the second-last year of school, and Integration we do in the last year. The extent to which you do them is dependent on which maths course you take. Most students who do integration only do the basic integration, but things like volumes of revolution, integration by parts, partial fractions (I dunno how many people here would know what I'm talking about any more) are taught to advanced students.
Wow! Math on the DS! My children will be so addicted to this game that they will be able to get good grades in schools...NOT!!
Okay, there have been way more than enough edutainment games for the DS.
Most of them are crap (Except for the My [Insert Language Here] coach games) and need to be killed. They are educational, but they are not entertaining.
How about Nintendo publishes a REAL edutainment game...MATH BLASTER! I loved to play MATH BLASTER all the time at school! I beat that game like 10 times on the hardest difficulty! I got good grades on math too! Now THAT is edutainment!