Neurobics: More Than the Sum of Its Parts

Neurology Now
November/December 2009
Volume 5(6)
p 9
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I just picked up my September/October 2009 issue of Neurology Now, turned to page 13, and saw your “Sum Snap” puzzle. Challenge #2 asks, “How many chains of same-colored circles can you find that add up to 10?” My answer was five, but when I turned to page 14, I saw that the answer was supposed to be four. In fact, I was correct: There are three chains of circles colored green that add up to 10. The answer sheet correctly identified the chains 5-3-2 and 3-2-1-4. I found these as well; however, the green circle chain 1-4-5 wasn't identified.

Kevin Pettit, Ph.D.

Boulder, CO

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