100%

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A web site informs me that today is a day with a full moon.

How much of the moon is visible?

"100% is the answer supplied.

And yet, of course, it is not 100% -- it is 50% at most.

I wonder how much data falls into the same category ... a damned-sure 100% that is not 100% at all.

I'm not 100% certain.
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