Some fascinating Numbers

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					Recreational Math-
Mathemagics
        J. Sriskandarajah
       AMATYC Conference
  Las Vegas, November 13, 2009
1776 and Abraham
Lincoln (02-12-1809)
• 1776 is not only a significant
  year, it’s a fascinating number!

• Think of a positive single digit
What’s fascinating about
1089?
• Write any non symmetric three digit
  number
• Reverse your original number
• Express the positive difference as a
  three digit number
• Now reverse this difference
• Then add the above two numbers
• The answer is…….
Learn more about 1089

• It’s a perfect square, 33^2

• It’s the only four digit number
  when multiplied by 9 will
  produce its original number in
  reversed order: 9801 which is
  another perfect square, 99^2
Become a psychic in 2009
Age by dining out?
• Pick the number of times a week you
  would like to dine out (0-7)
• Times this number by 2
• Add 5 to this number
• Multiply this by 50
• If you have already had your birthday
  this year add 1759, else add 1758
• Subtract the four digit year you were
  born
Chocolate Math

• The above activity could be
  rephrased as seen in the
  following link:
• H:www.matcmadison.edu\jsrisk
  andara\My
  documents\Chocolate Math
• Note, 2009 is NOT prime but
  7X7X41
Mathemagics and
Recreational Mathematics
continued…..
• Mind Reading
• Super Computation
• Spelling and the Math
  connection
• Predicting a three digit number,
  house number, card etc.,
Is 2009 special?


    Number   a 7X7 square,   1-49
    1 2       3   4   5       6     7
    8 9       10 11 12        13    14
    15 16     17 18 19        20    21
    22 23     24 25 26        27    28
    29 30     31 32 33        34    35
    36 37     38 39 40        41    42
    43 44     45 46 47        48    49
Interchange rows
randomly
•   15 16   17   18   19   20   21
•   36 37   38   39   40   41   42
•   1 2     3    4    5    6    7
•   22 23   24   25   26   27   28
•   43 44   45   46   47   48   49
•   8 9     10   11   12   13   14
•   29 30   31   32   33   34   35
Now interchange
columns randomly
•   17   21   15   20   18   16   19
•   38   42   36   41   39   37   40
•   3    7    1    6    4    2    5
•   24   28   22   27   25   23   26
•   45   49   43   48   46   44   47
•   10   14   8    13   11   9    12
•   31   35   29   34   32   30   33
Add 262 to every entry

•   279   283   277   282   280   278   281
•   300   304   298   303   301   299   302
•   265   269   263   268   266   264   267
•   286   290   284   289   287   285   288
•   307   311   305   310   308   306   309
•   272   276   270   275   273   271   274
•   293   297   291   296   294   292   295
Add the seven numbers
on either diagonal, aha!
• 279+304+263+289+308+271+29
  5 = 2009!

• 281+299+266+289+305+276+29
  3 = 2009!
For an even more
amazing result,
• Highlight any entry on the table
  and cross out all the other
  entries in the same row and
  column. Continue this process
  with the remaining entries until
  you have just seven entries all
  on different rows and columns.
Amazing sum of 2009!
        283
                          301
              263
                                      288
                    310
 272
                                292

 272+283+263+310+301+292+283 =2009!!

				
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posted:10/3/2012
language:English
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