November 19, 2008

• Zachary’s teachers tell me that he likes writing numbers. His speech therapist even says he has “an unusual gift with numbers.” They tell me that sometimes he writes in order (ie. 1-100) and sometimes it’s “random.” Now, I’m not a math major, but I do know that true randomness is nontrivial. Especially for a 4-year-old.

  (says: 15111929415573)

  So here’s the puzzle of the day. Tell me why the last digit is wrong and what it should be.

  (Post has been modified: The last 1 digit is incorrect, not the last 2 – thanks babytaz113 for catching it!)

  • 1:30 pm
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