Did we invent math or did we discover it?

Mathematics is not discovered, it is invented

Maths can be said as both invented as well as discovered.

Like for example, if we take the Pythagoras theorem, what the theorem is based on was already existing (in sense, the sum of the altitude ² + base² was already = hypotenuse ² even without any proof, in a right angled triangle).

But for the various ways to prove the theorem, lots of formula had to be invented.

Hope this helps you...