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Treebeard's Stumper
17 December 1999

Millennium Magic

I think of the Y2K New Year as an odometer day, when digits reset to zero. It's just a number thing, so here's another. Circle any number on the grid below, and then cross out all the other numbers in its row and column. Now circle any remaining number and cross out all the others in its row and column. Do it again, and again, and then circle that last remaining number. The sum of your five circled numbers will always be 1,999! Can you make your own magic grid that adds up to 2000 for the new year? How does this work? How many solutions are there?

  296     456     319     287     324  
  452     612     475     443     480  
  313     473     336     304     341  
  420     580     443     411     448  
  316     476     339     307     344  

When you're done the grid might look like this,
though you'll probably select different numbers:

420 + 473 + 475 + 307 + 324 = 1,999

Answer


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Copyright © 1999 by Marc Kummel / mkummel@rain.org