[Tutor] strange output

[Pijus Virketis]

Hi,

not that this is very significant, but perhaps someone can explain this
curious bit of output?

Python 2.1 (#15, Apr 16 2001, 18:25:49) [MSC 32 bit (Intel)] on win32
Type "copyright", "credits" or "license" for more information.
IDLE 0.8 -- press F1 for help
>>> 4.2-2.5
1.7000000000000002 <-- ?!? Where do we get this miraculous digit?

>>># just for comparison ...
>>> 7.0-4.0
3.0 <-- All's well ...
>>> 

Cheers, 

Pijus
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