Can anybody please explain me why the result of 2.05 - 0.05 isn't 2?

Question

https://code.sololearn.com/c31mxWyEkjK6/?ref=app

Answer 1

Please refer:

https://stackoverflow.com/questions/588004/is-floating-point-math-broken

Answer 2

Thanks to @Hatsy Rei's link, I found a simpler but inaccurate explanation:
http://floating-point-gui.de/basic/