Now this is a clock for math whizzes! The clock sports math equations involving the number 9 and is made by the Triple Nine Society, a high-IQ organization:

Each number is expressed as a calculation involving three instances of the number 9.

For example, 5 o'clock is the square root of nine (3), factorial (3x2x1 = 6), minus 9/9 (6-1 = 5).

The trickiest time is 7 o'clock, whose calculation works out to 6.99999..., with an infinite number of nines. Wikipedia assures us that 0.99999... really does equal 1, so no worries that the clock is cheating there.

Love it. Obviously you don't need to know the math behind it to figure out what time it is, but it's a cute exercise to work it all out.
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Math "whiz"? Yeah, figuring out the square root of 9 is pretty challenging.

I'd say it's geeky and suitable for a math teacher's classroom, but not quite "whiz level". It's probably beyond about the top 5% of U.S. government school teenagers, though. Cute.
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Why do you need Wikipedia to tell you that .999(9) is equal to 1? The proof is three lines long:

Let S = 0.999(9)
Then 10*S = 9.999(9)
10*S - S = 9 --> 9S = 9 --> S = 1

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Some of those are just needlessly complicated. The square root of nine plus nine minus nine? Come on. That's not clean at all.
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It's pretty amazing! Nice clock for math whizzes. I like it!
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