I'm not a programmer, but IIRC normal division, as shown (4/5), used to do integer division, but now in python 3 it follows the behavior you show. Notice the

I'm not a programmer, but IIRC normal division, as shown (4/5), used to do integer division, but now in python 3 it follows the behavior you show. Notice the "from __future__ ..."line implies that the following lines all follow the python 3 behavior, I assume from 2.6.