This is Malcolm Gladwell nonsense and not backed up by the fact that Chinese-Americans who learn English first (e.g. Nobel laureate Steven Chu) do just as well as their Chinese counterparts.
But we're talking about an entire country in which most people don't speak English at all. If I have to tell my 55 year old aunt to go to www.hotmail.com then I'd have to spend half an hour describing what English letters to type.
I can imagine it's something like explaining how to change some obscure setting through a GUI interface over the phone, but significantly worse.
On one hand you have: "OK, do you see a button in the lower left? Click that. Now press "Options", then "Configure". What? You don't see those? Which button did you click? ..."
On the other hand you have: "OK, do you see the button that looks like a squiggly line? It's in the top-leftish corner, between the button that has a circle with a small line through it and a button that looks like a comb. Press that one three times..."
It's not about being good at math, just at memorizing numbers. I'm Chinese American and was considered to be "good-at-math" in grade school, but damned if I can remember long sequences of numbers. Maybe I should try thinking about them in Chinese.