why for -2< x< -1 the fractional part is x+2

 It's an interesting thing that I faced today. 

Actually if we look at the number line it looks like...

Here something called x standing between -2 and -1 

Now the main matter is that the fractional part associated with it is not the portion between -1 and the number.

Rather it is the portion between the number and -2

So to get that we have to subtract -2 from x

As a result the fractional part comes out to be

x-(-2) = x+2