Who invented the subject mathematics and why?

Answer 1

Nobody "invented" mathematics. It is not a science, but a property of the natural world. 1+1 always equal 2 - nobody can invent that. The square of the hypotenuse of a right-angled triangle is always the sum of the squares of the other two sides, regardless of when someone discovers it. It remains true on lifeless planets where there is no one to draw a triangle or measure the sides.

No single person discovered mathematics and mathematical systems have been developed by different cultures at different times - sometimes independently (for example Liebnitz and Newton's calculus). The mathematics in the Western Hemisphere can mostly be traced to roots in Mesopotamia, Egypt (especially for geographical use) and Babylon (especially for astronomical use). The strict concept of proofs and even axiomatising geometry is of Greek origin. Although Euclid is said to have played a major part, this development is not attributable to a single inventor. The use of zero, which enabled the concept of place values and our modern number system was developed in India. More recently, there have been axiomatic geometries developed that are very different from the Greek geometries. Modern number theory was axiomatised in the mid 19th Century.

Like most other fields of knowledge, there are new branches of mathematics being developed all the time. And that will continue.

Mathematics was developed in different capacities by many different civilizations, including the Chinese, Greeks, Mayans, and Arabs, to name a few.