Maths is correct in English as it's a plural noun for the mathematic disciplines (arithmetic, calculus, algebra, geometry etc). It's incorrect in American English however.
"There are logical arguments for both spellings. The word “mathematics” can be considered as a singular and as a plural noun. Both the Oxford and the Merriam-Webster dictionaries say the word is plural – hence the s on the end – but also that it is usually used as if it was a singular noun. So, most people would say “mathematics is my best subject” and not “mathematics are my best subject”. The shortened form “maths”, then, makes sense because the word is still a plural noun and so should still have the “s” on the end. On the other hand, it could be argued, “math” makes sense because it seems wrong to remove the letters “ematic” from the middle of the word and leave the final “s”."
http://www.dailywritingtips.com/math-or-maths/
Edit: In fact, The United States and Canada are the only English speaking countries that don't use Maths as opposed to Math.
