What is the difference between Python & Python 3 ?

Answer 1

No you don't need to learn all versions of python focus only on python3 version and become expert of it.

If you want to do android development in python then you need to learn kivy,tkinter frameworks of python.

Answer 2

Python is programming language and python3 just the version of the python.python has many versions like python2.x , python3.x, etc. But now days python3.x is mostly uses.

Answer 3

If i want to programme a android app then i have learn all python versions?