In the U.S. I would study math. In Britain, I would study maths. What gives?
There's a lot of debate about which is right (!), but not much about why there's a difference - good question.
I found this:
Unfortunately this information is unattributed, but it's the only theory I can dig up. In full here: http://www.answerbag.com/q_view/15988#ixzz1DPW8I322
Math or Maths are shortenings of "mathematics". As mathematics is a plural it is generally held that the abbreviation should be a plural (except in the US). Thus "maths"
Although "math" is widely adopted It isn't correct.