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bonanova - your magic trick reminded me of this one I saw about 10 years ago.

1) Pick a number between 1 and 9

2) Subtract 5

3) Multiply by 3

4) Square the number

5) Add the digits of that number together, for example, if you number is

83, you would add 8 and 3 and get 11.

6) If the resulting number is less than 5, add five, otherwise subtract 4

7) Multiply by 2

8) Subtract 6

9) Assign a letter to your number. A=1, B=2, C=3, D=4, E=5, etc

10) Pick a country that begins with your letter

11) Pick an animal that begins with the second letter from your country

12) think of the color of that animal....

Grey Elephant from Denmark!

:D

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It looks like this is based off the fact that multiples of 9 will have a digit sum of 9 as used in step 5. Steps 3 and 4 make your original integer into a multiple of 9 because you are multiplying by 3 and then squaring the number, so there will be two 3's in its prime factorization making it a multiple of 9 every time.

Step 6 handles the possibility of your number being zero, which was introduced by the addition of step 2 which didn't seem necessary other than to make the integers smaller and the math easier for people to do in their head. So by the end of step 6 the number is guaranteed to be 5 every time, either (0+5) or (9-4). It doesn't matter what happens afterwards, except that as Andromeda pointed out, there are other countries that start with D besides Denmark. Interesting trick though. :D

Since we know that the number is always 5 at the end of step 6, maybe the steps after that can be modified so that the result is a number where there is only one country to choose from with that letter? Does anyone know of a letter where there is only one country in the world beginning with that letter? Qatar maybe? I don't have an answer for this, just thought it might be interesting to think about.

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Interesting thinking Sinistral

Oman

Qatar

Yemen - this one is the best solution because there are not many animals that start with letter 'E' and usually the first animal that pops up in your mind is elephant!

:)

EDIT: One problem though

:huh:

Who would think of Yemen?!

Edited by andromeda
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andromeda :) I loved your other answers.

Sinistral you are correct except that step 6 guarantees the number is 4 not 5. Of coruse the math is is designed to get you to D. now for the other stuff yeah you might not think of Denmark first, but *usually* people will, then e usually makes you think of an elephant. its not perfect, but neat when it works.

O - there is only one Oman but again not a well known country.

D - is actually a pretty good choice as there are only 4, with denmark being the one thought of most

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