FREE TAPATALK APP

hard_head · 4th February 2003, 10:23 AM

A psychic webpage that will amaze and amuse.
Confuse your co-workers, win some cash.

Psychic Webpage

MRC_Hans · 4th February 2003, 10:33 AM

Funny, it works some of the time, other times its consistently off. I think I read about this trick, but I dont remember the details.

Hans

Stimpson J. Cat · 4th February 2003, 10:39 AM

It's simple. Your number will always be a multiple of 9.

10a + b - a - b = 9a

where a is the first digit (10s place), and b is the second digit (ones place).

They just produce a random sequence of symbols, and make sure that every 9th symbol is the same.

Dr. Stupid

hard_head · 4th February 2003, 10:47 AM

Indeed, but it is amazing how quickly some folks think the computer is really doing something extraordinary. And then get PO'd when you explain it to them. No wonder psychic hotlines rake in the bucks.

Hans check your math again, I've done it for dozens of numbers and it always works.

Hellbound · 4th February 2003, 11:13 AM

Stimpy's right. Your final number will always be a multiple of 9:

10-(1+)=9
11-(1+1)=9
12-(1+2)=9
...
21-(2+1)=18
22-(2+2)=18
...
57-(5+7)=45

So, in each iteration, the symbols for 9,18,27,36,45,54,63,72,81, and 90 will be identical.

The symbols for these numbers change each time the page loads, so you get a different "final" symbol each time.

Underemployed · 4th February 2003, 11:42 AM

I was just wiling away some time when I suddenly noticed that every multiple of the number nine can be reduced to the number nine by adding up the resulting digits.

9 x 9 = 81 ---> 8 + 1 = 9

9 x 4 = 36 ---> 3 + 6 = 9

9 x 65352 = 588168 ---> 5 + 8 + 8 + 1 + 6 + 8 = 36 ---> 3 + 6 = 9

I have not done any proofs for this being correct up to infinity as I have no idea how. But I suspect it would be true for nine times any whole number.

Numbers 1-8 do not have this property. Is there something a real mathematician can tell me about the number nine? I can't be the first person to notice this (this psychic trick is probably based on this property nine has) but I have very little grounding in formal mathematics.

Coincidentally, I was born on the 9th of September...(but not on a year ending nine, drat)

Hellbound · 4th February 2003, 11:44 AM

Because it's a base-10 system. Same reason the psychic page works as it does.

In both instances, it would be different for a different system. In base 8, 7 would be the magic number. In hexadecimal, F would be it. In base 12, it would be 11, and so on.

It's simply an artifact of the way we write numbers; the fact that we "roll over" to a new column at 10 (in our system).

jj · 4th February 2003, 12:58 PM

Hey, like wow, man, it's the casting out 9's magic trick!

It is nicely disguised, though. Still all it does is figure out how to subtract the 9's residual from the number, the same way that I used to figure out the residual to test arithmetic.

In any base, it works for the number base-1. In hex, it would be "casting out 'F's"

Underemployed · 4th February 2003, 01:51 PM

This forum is better than here for quick answers! Thanks.

On an aesthetic note, it is easy to spot even if you don't know any maths - the signs are all in neat rows and the numbers make it easy after a few times to see every guess results in a multiple of nine. If I did this trick, I'd arrange them in a pyramid or a spiral and swap numbers for letters. That would slow down any ill-informed skeptics.

xouper · 11th February 2004, 09:54 AM

bump

T'ai Chi · 15th January 2006, 09:14 AM

old thread, but what the heck

http://www.statisticool.com/mindreader.htm

is my explanation, and

http://www.statisticool.com/digitalroot.htm

explains a similar but slightly more involved number trick.

4th February 2003, 10:23 AM	#1
hard_head New Blood Join Date: Jul 2001 Posts: 7	Amaze your friends, win the million dollar challenge... A psychic webpage that will amaze and amuse. Confuse your co-workers, win some cash. Psychic Webpage
hard_head New Blood Join Date: Jul 2001 Posts: 7	__________________ Only Sheep Need a Shepherd

4th February 2003, 10:33 AM	#2
MRC_Hans Penultimate Amazing Join Date: Aug 2002 Location: Whithin earshot of the North Sea Posts: 16,604	Funny, it works some of the time, other times its consistently off. I think I read about this trick, but I dont remember the details. Hans
	__________________ Don't. Just don't.

4th February 2003, 10:39 AM	#3
Stimpson J. Cat Graduate Poster Join Date: Sep 2001 Location: Oxford, UK Posts: 1,833	It's simple. Your number will always be a multiple of 9. 10a + b - a - b = 9a where a is the first digit (10s place), and b is the second digit (ones place). They just produce a random sequence of symbols, and make sure that every 9th symbol is the same. Dr. Stupid
	__________________ A poke in the eye makes Baby Jesus cry.

4th February 2003, 10:47 AM	#4
hard_head New Blood Join Date: Jul 2001 Posts: 7	Indeed, but it is amazing how quickly some folks think the computer is really doing something extraordinary. And then get PO'd when you explain it to them. No wonder psychic hotlines rake in the bucks. Hans check your math again, I've done it for dozens of numbers and it always works.
hard_head New Blood Join Date: Jul 2001 Posts: 7	__________________ Only Sheep Need a Shepherd

4th February 2003, 11:42 AM	#6
Underemployed Muse Join Date: Jan 2003 Posts: 764	I was just wiling away some time when I suddenly noticed that every multiple of the number nine can be reduced to the number nine by adding up the resulting digits. 9 x 9 = 81 ---> 8 + 1 = 9 9 x 4 = 36 ---> 3 + 6 = 9 9 x 65352 = 588168 ---> 5 + 8 + 8 + 1 + 6 + 8 = 36 ---> 3 + 6 = 9 I have not done any proofs for this being correct up to infinity as I have no idea how. But I suspect it would be true for nine times any whole number. Numbers 1-8 do not have this property. Is there something a real mathematician can tell me about the number nine? I can't be the first person to notice this (this psychic trick is probably based on this property nine has) but I have very little grounding in formal mathematics. Coincidentally, I was born on the 9th of September...(but not on a year ending nine, drat)
Underemployed Muse Join Date: Jan 2003 Posts: 764	__________________ There is no punchy, conclusive final sentence for this post.

4th February 2003, 11:13 AM	#5
Hellbound Abiogenic Spongiform Join Date: Sep 2002 Location: In a handbasket Posts: 9,029	Stimpy's right. Your final number will always be a multiple of 9: 10-(1+)=9 11-(1+1)=9 12-(1+2)=9 ... 21-(2+1)=18 22-(2+2)=18 ... 57-(5+7)=45 So, in each iteration, the symbols for 9,18,27,36,45,54,63,72,81, and 90 will be identical. The symbols for these numbers change each time the page loads, so you get a different "final" symbol each time.

4th February 2003, 11:44 AM	#7
Hellbound Abiogenic Spongiform Join Date: Sep 2002 Location: In a handbasket Posts: 9,029	Because it's a base-10 system. Same reason the psychic page works as it does. In both instances, it would be different for a different system. In base 8, 7 would be the magic number. In hexadecimal, F would be it. In base 12, it would be 11, and so on. It's simply an artifact of the way we write numbers; the fact that we "roll over" to a new column at 10 (in our system).

4th February 2003, 12:58 PM	#8
jj grumpy old skeptic Join Date: Oct 2001 Location: Deep in the rain Posts: 18,711	Hey, like wow, man, it's the casting out 9's magic trick! It is nicely disguised, though. Still all it does is figure out how to subtract the 9's residual from the number, the same way that I used to figure out the residual to test arithmetic. In any base, it works for the number base-1. In hex, it would be "casting out 'F's"
	__________________ The Power to Quit

4th February 2003, 01:51 PM	#9
Underemployed Muse Join Date: Jan 2003 Posts: 764	This forum is better than here for quick answers! Thanks. On an aesthetic note, it is easy to spot even if you don't know any maths - the signs are all in neat rows and the numbers make it easy after a few times to see every guess results in a multiple of nine. If I did this trick, I'd arrange them in a pyramid or a spiral and swap numbers for letters. That would slow down any ill-informed skeptics.
Underemployed Muse Join Date: Jan 2003 Posts: 764	__________________ There is no punchy, conclusive final sentence for this post.

11th February 2004, 09:54 AM	#10
xouper Banned Join Date: Jan 2002 Posts: 2,189	bump
xouper Banned Join Date: Jan 2002 Posts: 2,189

15th January 2006, 09:14 AM	#11
T'ai Chi Penultimate Amazing Join Date: May 2003 Posts: 11,235	old thread, but what the heck http://www.statisticool.com/mindreader.htm is my explanation, and http://www.statisticool.com/digitalroot.htm explains a similar but slightly more involved number trick.
	__________________ http://www.statisticool.com