BEATCALC:  Beat the Calculator!

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Back to Calculation Tips & Tricks
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From the BEATCALC mailing list:
a weekly service from B. Lee Clay, archived here by the Math Forum.
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   Find the difference of the squares of two
               consecutive 2-digit numbers

  1. Select two consecutive 2-digit numbers.
  2. Add the two 2-digit numbers!

   Examples:

  1. 24 + 25 = 49. (Try it on a calculator and see, or if you're really sharp, do it mentally: 24 x 24 = 576, 25 x 25 = 625, 625 - 576 = 49.)

  2. If 63 and 64 are selected, then 63 + 64 = 127. (For larger number addition, do it in steps: 63 + 64 = 63 + 60 + 4 = 123 + 4 = 127.)


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14 January 1996
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