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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   Squaring special numbers (2 and
                 repeating 3's)

  1. Choose a number with a 2 and repeating 3's.
  2. The square is made up of:
    • first digits: 5 & one fewer 4 than repeating 3's
    • next digits: 2 & one fewer 8 than repeating 3's
    • last digit: 9

   Example:

  1. If the number to be squared is 2333:
  2. The square has:

    first digits: 5 and one fewer
        4 than 3's                      5 4 4
    next digits: 2 and one fewer
        8 than 3's                            2 8 8
    last digit: 9                                   9

  3. So 2333 x 2333 = 5442889.

   See the pattern?

  1. If the number to be squared is 233333:
  2. The square has:

    first digits: 5 and one fewer
       4 than 3's               5 4 4 4 4
    next digits: 2 and one fewer
       8 than 3's                        2 8 8 8 8
    last digit: 9                                  9

  3. So 233333 x 233333 = 54444288889.
     


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20 July 1998
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