Is this statement regarding mathematics true? (yes basic)

[TalkOrigin]

I'm clueless on mathematics and will soon begin the long road into its academic study. I saw this statement on the following website:
http://everything2.com/title/the+difference+between+mathematics+and+physics

the last poster says this:

"sometimes mathematics makes assumptions different to what holds in the real world. If I draw a triangle around the sun, the angles will add up to more than 180° because gravity curves space. Mathematics works only within the assumptions you put into it."

Is this true? Kind of goes against what I would assume is the purpose of mathematics (I thought mathematics was a expression of reality not dependent upon variables of reality?)

Thanks, and yes I know this is basic!

 

[CRGreathouse]

It's not really all that basic; no need to apologize. The poster appears to be talking about non-Euclidean geometries, specifically elliptic geometry. So yes, it's real.

 

[TalkOrigin]

Thanks =)

Well, that completely shattered any thoughts I had on mathematics haha