I start Python Programming Language in these days, when i was trying to understand them

i come across to these problems so i will be so happy if you help me in :

1)

```
>>> # Integer division returns the floor:
... 7/3
2
>>> 7/-3
-3
```

I can't understand this becuase as normal 7/3 is not 3 or 7/-3 is not -3.

2)

In here :

```
>>> tax = 12.5 / 100
>>> price = 100.50
>>> price * tax
12.5625
>>> price + _
113.0625
>>> round(_, 2)
113.06
```

I don't know this : (price+_) and also [ round(_,2)]