Is everyone such this retarted in US? I am baffled by this guy.
A quick view of what is a "fact" in math really by Deceiver.
Once upon a time mathematicians used some tools like numbers, multiplication or even integrals without really knowing what the fuck are they. Then, in XIX century there came a group of guys who had this crazy idea to create mathematicial theory of everything, they wanted to create some fundamentals of math. Bertrand Russel tried logic, but he failed. Many others tried but finally someone tried to build math upon group theory. That was great success! Zermelo and Fraenkel in the very beggining of XX century create their so called "axioms". It was a set of fundamental assumptions on which they wanted to create whole math theory! They found out that with sets and simple operations on them they can define everything else - integers, real number and so on. Unfortunatelly some nasty troll called Goedel proven later on that not every theorem can be proven using those axioms, or in fact any axioms at all. There are some theorems which are proven to be "unprovable", like hypothesis that there exist some set that is larger than set of natural numbers and smaller than set of real numbers.
Of course, you don't have to prove anything using just those axioms, or any axioms at all. In practice you just use arleady proven theorems to prove your brand new theory. But when you use magnifying glass behind every theorem lies just sets and operations on them.
Hope it helped.