Cool Trick.

[jmatt]

The Link

It has gotten my number right every time...

All I can say is it's a cool trick, and a trick is all it is.

 

[formermav43]

It's cool. Until you realize that your number will always be a multiple of 9, and all of those symbols are the same.

 

[Genco]

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[jmatt]

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[AeroHorn]

The answers are the same group of numbers for any number you think. And these group of numbers have the same symbol. You can verify this by noting the number on your first try and then when trying the next number, look at the symbol for the current and previous answers. They are the same.

Let's say the 2-digit number you choose is represented as "nm"
This can be written algebraically as 10n + m.
The problem asks you to substract the sum of the digits from the number, which is
10n + m - (n + m) = 9n.

So, for n=1 to 9, (n <> 0 because it is a 2-digit number), you have nine numbers. Just assign them the same symbol and show that symbol regardless of what number the user "thinks".

 

[Alum03]

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