Recreational Math- Mathemagics J. Sriskandarajah AMATYC Conference Las Vegas, November 13, 2009

1776 and Abraham Lincoln ( ) 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: 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,

Interchange rows randomly

Now interchange columns randomly

Add 262 to every entry

Add the seven numbers on either diagonal, aha! = 2009! = 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! =2009!!