Natural Vs Humanly Created Artificial Mathematics

There are possibly two types of mathematics: Often the word "Mathematics" seems to be misused while concluding about the  Mathematical Realities ! 

One which exists Naturally like Pythagoras Theorems, Geometrical Truths (Unchangeable) 

Second Humanly created Mathematics like Imaginary Numbers etc..(Changeable) 

One needs to be careful which mathematics is being referred while concluding about mathematical realities as a whole !