Posted by: Alexandre Borovik | June 4, 2013

A professional skill: parsing

 

 

 

 

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I am proud that, after marking 220 examination scripts in first year linear algebra , I was still able to locate, at a glance, an error in this picture — thanks to skills in parsing of meaningless symbolic input developed over many years of teaching mathematics.

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Responses

  1. Apart from the error (which indeed strikes the eye, since 9! is far beyond the range 1..12), why 1=9/9 is out of step? can’t one express 1 via three 9’s and not two?

  2. A good point: of course, 1 can be expressed via three 9’s.

  3. You are a professional indeed :)

  4. $9^{9-9}$

  5. Ahh, they meant to use those symbols in the opposite order. I wonder where the error crept in. Did someone give handwritten diagrams to someone else, who put it into a computer system wrong? Except for the errors, I love this clock. So much more accessible for students than the other math clocks I’m familiar with. Maybe I’ll search for a site that let’s you make your own, and get a four 4’s clock made.

  6. First google hit for four fours closk is hilarious: http://www.taliscope.com/clock_4444_Base.html

  7. My big problem with this clock, is it assumes no negative hours can exist but uses roots!


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