Sorry to jump in so late but this is a fascinating argument. It depends on what you mean by "mathematics".
Broadly speaking, we have two big high-level branches, pure and applied mathematics. Applied mathematics attempts to describe relationships between things in the physical universe. As such, the language, forms and methods are invented, but the relationships we try to describe are discovered, and of course new ones are discovered all the time.
Pure mathematics is the study of formal structures and systems, all of which were invented. There is no such thing as "two". We created this; now, if it so happens that you have a pencil and another pencil, and you agree we can use "two" to describe something about your pencil collection, well then, wonderful and God bless you.
So I think the passionate discussion about this is quite legitimate; it is not a simple question to answer.
Regards,
Scott Anderson
Instructor in Mathematics (whatever that is)
University of Detroit Mercy
Detroit MI