why do I get this behavior from a while loop?

[S. Chris Colbert]

This seems strange to me, but perhaps I am just missing something:

In [12]: t = 0.
In [13]: time = 10.

In [14]: while t < time:
   ....:     print t    
   ....:     t += 1.    
   ....:                
   ....:                
0.0                     
1.0                     
2.0                     
3.0                     
4.0                     
5.0                     
6.0                     
7.0                     
8.0                     
9.0                     

In [15]: t = 0.

In [16]: time = 10.

In [17]: while t < time:
   ....:     print t    
   ....:     t += 0.1   
   ....:                
   ....:                
0.0                     
0.1                     
0.2                     
0.3                     
<--snip-->
9.4
9.5
9.6
9.7
9.8
9.9
10.0


I would think that second loop should terminate at 9.9, no? 

I am missing something fundamental?

Cheers!

Chris