# How The &%^$#!!! Does This Work????

**URL:** <https://boards.straightdope.com/t/how-the-does-this-work/344185>\
**Category:** Miscellaneous and Personal Stuff I Must Share\
**Created:** [February 13, 2006, 12:07am UTC](https://boards.straightdope.com/t/how-the-does-this-work/344185 "2006-02-13T00:07:02Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![PapSett](https://avatars.discourse-cdn.com/v4/letter/p/ecc23a/32.png) [@PapSett](https://boards.straightdope.com/u/PapSett)\
**Post date:** [February 13, 2006, 12:07am UTC](https://boards.straightdope.com/t/how-the-does-this-work/344185/1 "2006-02-13T00:07:02Z")

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[http://www.zapdramatic.com/swf/psychicted.swf](http://www.zapdramatic.com/swf/psychicted.swf)

Sorry if this has been posted before, but I just ran across it while surfing, and for the life of me I can’t figure out how it works…

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**Author:** ![bouv](https://avatars.discourse-cdn.com/v4/letter/b/bc8723/32.png) [@bouv](https://boards.straightdope.com/u/bouv)\
**Post date:** [February 13, 2006, 12:09am UTC](https://boards.straightdope.com/t/how-the-does-this-work/344185/2 "2006-02-13T00:09:20Z")

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Your answer will always be a multiple of nine. All multiples of nine have the same symbol, though that symbol is not consistant between each “instance” of the game, to fool you.

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**Author:** ![Eleusis](https://avatars.discourse-cdn.com/v4/letter/e/f4b2a3/32.png) [@Eleusis](https://boards.straightdope.com/u/Eleusis)\
**Post date:** [February 13, 2006, 12:11am UTC](https://boards.straightdope.com/t/how-the-does-this-work/344185/3 "2006-02-13T00:11:50Z")

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> [@PapSett](#):
>
> [http://www.zapdramatic.com/swf/psychicted.swf](http://www.zapdramatic.com/swf/psychicted.swf)
> 
> Sorry if this has been posted before, but I just ran across it while surfing, and for the life of me I can’t figure out how it works…

Yeah it’s been posted before under various incarnations.

The idea that when you add the two digits and subtract them from the original, you always up with a multiple of 9.

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**Author:** ![eusta\_backhoe](https://avatars.discourse-cdn.com/v4/letter/e/aca169/32.png) [@eusta\_backhoe](https://boards.straightdope.com/u/eusta_backhoe)\
**Post date:** [February 13, 2006, 12:12am UTC](https://boards.straightdope.com/t/how-the-does-this-work/344185/4 "2006-02-13T00:12:58Z")

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Oddly enough, most “psychics”, plam readers and fotune tellers have a bundle of those kinds of tricks to fool the math-illiterate. What’s odd is that the readers may not understand how it works themselves, being seldom of a scientific bent, but know how it can make believers out of the gullible.

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**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\
**Post date:** [February 13, 2006, 5:05am UTC](https://boards.straightdope.com/t/how-the-does-this-work/344185/5 "2006-02-13T05:05:53Z")

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> [@PapSett](#):
>
> [http://www.zapdramatic.com/swf/psychicted.swf](http://www.zapdramatic.com/swf/psychicted.swf)
> 
> Sorry if this has been posted before, but I just ran across it while surfing, and for the life of me I can’t figure out how it works…

When you see something like this, particular like the one in the OP, just look at the sybol you get. Then say “hey, what if I picked a different number?” Then do the sums for a different number, you’ll quickly realise what’s going on when every number leads you to the same symbol.

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**Author:** ![SandyHook](https://avatars.discourse-cdn.com/v4/letter/s/dec6dc/32.png) [@SandyHook](https://boards.straightdope.com/u/SandyHook)\
**Post date:** [February 13, 2006, 5:53am UTC](https://boards.straightdope.com/t/how-the-does-this-work/344185/6 "2006-02-13T05:53:52Z")

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A slightly different way to answer the already answered question is as follows:

Any two digit number starting with 9 will always give 81 as an answer.

Any two digit number starting with 8 will always give 72 as an answer.

Any two digit number starting with 7 will always give 63 as an answer.

and so on.

This set of answers (81, 72, 63, 54, 45, 36, 27, 19, 9) always have the same symbol, even though that symbol changes from game to game.

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**Author:** ![PapSett](https://avatars.discourse-cdn.com/v4/letter/p/ecc23a/32.png) [@PapSett](https://boards.straightdope.com/u/PapSett)\
**Post date:** [February 13, 2006, 1:45pm UTC](https://boards.straightdope.com/t/how-the-does-this-work/344185/7 "2006-02-13T13:45:19Z")

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Thanks for the answer ! Now I feel sorta stupid :o . I knew there was a catch to it, but since I am not mathematically inclined…
