# Some fascinating Numbers by lr8cj8E

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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
1089?
• Write any non symmetric three digit
number
• Express the positive difference as a
three digit number
• Now reverse this difference
• Then add the above two numbers

• 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
• Subtract the four digit year you were
born
Chocolate Math

• The above activity could be
rephrased as seen in the
andara\My
documents\Chocolate Math
• Note, 2009 is NOT prime but
7X7X41
Mathemagics and
Recreational Mathematics
continued…..
• 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

•   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
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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