Hi,

This little trick is quite cool. 10 points to the first person to post the 'reason' why this always works.
  http://digicc.com/fido/
(click the little guy in the bottom right to proceed to next page etc)

Regan

Regan Heath wrote:
> Hi,
> 
> This little trick is quite cool. 10 points to the first person to post the  'reason' why this always works.
>   http://digicc.com/fido/
> (click the little guy in the bottom right to proceed to next page etc)
> 
> Regan
Doesn't work if you pick a number with the same digits - ie 555

Brad

Regan Heath wrote:
> Hi,
> 
> This little trick is quite cool. 10 points to the first person to post the  'reason' why this always works.
>   http://digicc.com/fido/
> (click the little guy in the bottom right to proceed to next page etc)
> 
> Regan

would be better if the flash wasn't as annoying :-/ hard to read with all those distractions in the background and constant sound effects

Regan Heath wrote:
> Hi,
> 
> This little trick is quite cool. 10 points to the first person to post the  'reason' why this always works.
>   http://digicc.com/fido/
> (click the little guy in the bottom right to proceed to next page etc)
> 
> Regan

Here's my solution in D :)

int marked(int[] num){
    assert(num.length);
    int j;
    foreach(int i; num){
        assert(1<=i && i<=9);
        j+=i;
    }
    return 9-j%9;
}

On Thu, 10 Mar 2005 10:47:24 +1300, <brad@domain.invalid> wrote:
> Regan Heath wrote:
>> Hi,
>>  This little trick is quite cool. 10 points to the first person to post the  'reason' why this always works.
>>   http://digicc.com/fido/
>> (click the little guy in the bottom right to proceed to next page etc)
>>  Regan
> Doesn't work if you pick a number with the same digits - ie 555

No surprises there :)

It does ask for a 4 digit number with "lots of different digits" in it.

Regan

On Wed, 09 Mar 2005 18:28:29 -0500, clayasaurus <clayasaurus@gmail.com> wrote:
> Regan Heath wrote:
>> Hi,
>>  This little trick is quite cool. 10 points to the first person to post the  'reason' why this always works.
>>   http://digicc.com/fido/
>> (click the little guy in the bottom right to proceed to next page etc)
>>  Regan
>
> would be better if the flash wasn't as annoying :-/ hard to read with all those distractions in the background and constant sound effects

Yeah.. Don't blame me, I didn't write it :)

Regan

In article <opsnef8ijt23k2f5@nrage.netwin.co.nz>, Regan Heath says...
>
>On Thu, 10 Mar 2005 10:47:24 +1300, <brad@domain.invalid> wrote:
>> Regan Heath wrote:
>> Doesn't work if you pick a number with the same digits - ie 555
>
>No surprises there :)
>
>It does ask for a 4 digit number with "lots of different digits" in it.

Isn't that kind of like asking someone to "draw an 'S', and then a more different 'S'"?

- Eric Anderton at yahoo

I remember these from... like 10 years ago or more.  It's pretty simple.  First I'll walk through it:

Let's say you're given 1234 and 3412. You subtract:

3412 - 1234 = 2178

So the possibles are 1, 2, 7, 8.  Let's say you picked "2".... so 1, 7, and 8.  And it gets 2.  Amazing, you think?

Watch me with some other numbers:

4321 - 1234 = 3087
4231 - 1234 = 2997
4123 - 1234 = 2889
4132 - 1234 = 2898

Okay, that's enough of a sample.  Let's add now, a step it skips for you:

2 + 1 + 7 + 8 = 18
3 + 0 + 8 + 7 = 18
2 + 9 + 9 + 7 = 27
2 + 8 + 8 + 9 = 27
2 + 8 + 9 + 8 = 27

The real trick is, people think it knows your number.  It doesn't... it just knows the digits HAVE to add up to a multiple of nine, because you're subtracting digits from themselves (even in a funky order.)

The only problem is if you circle a NINE or a ZERO, you can't tell the difference.  That's why you're not allowed to circle zeros, which makes it certain that you're only circling 9's in that case.

I knew how this worked before I even learned real algebra ;).  Do I get 10 points now :P?

-[Unknown]


> Hi,
> 
> This little trick is quite cool. 10 points to the first person to post the  'reason' why this always works.
>   http://digicc.com/fido/
> (click the little guy in the bottom right to proceed to next page etc)
> 
> Regan

pragma wrote:
> In article <opsnef8ijt23k2f5@nrage.netwin.co.nz>, Regan Heath says...
> 
>>On Thu, 10 Mar 2005 10:47:24 +1300, <brad@domain.invalid> wrote:
>>
>>>Regan Heath wrote:
>>>Doesn't work if you pick a number with the same digits - ie 555
>>
>>No surprises there :)
>>
>>It does ask for a 4 digit number with "lots of different digits" in it.
> 
> 
> Isn't that kind of like asking someone to "draw an 'S', and then a more
> different 'S'"?
> 
> - Eric Anderton at yahoo


And maybe a wing...you know..if it's a ... wing-a-ling dragon...

And put one of those beefy arms back on for good measure :P

-- 
-PIB

--
"C++ also supports the notion of *friends*: cooperative classes that
are permitted to see each other's private parts." - Grady Booch

On Wed, 09 Mar 2005 23:03:46 -0800, Unknown W. Brackets <unknown@simplemachines.org> wrote:
> I knew how this worked before I even learned real algebra ;).  Do I get 10 points now :P?

Yes.

Regan