Higher math is about logic, abstractions and applying them to solve problems. Basic math is about holding bits of information in your head and manipulating them accurately. I absolutely believe that basic math taxes your working memory system more than advanced math does.
He also brings up the issue of regularity of eastern number systems making it much easier to do calculations in these languages - to an extent that it gives eastern children real advantage in math. Developmentally speaking.
I'll have to take a look at that book, sounds fascinating. Thanks.