[GeoStL] Re: NGR: Too Weird

ok maybe the algebra I gave was a bit vague --  I'll show my work.

A two digit number is composed of a number that is divisible by 10 (90, 80, 70, 
60, 50, 40, 30, 20, 10) and a number that is less than 10 (9,8,7,6,5,4,3,2,1)
That two digit number can be represented by:
10x + y
where x is the left digit, and y is the right digit.
The instructions say to take the two digit number, and from it we are to 
subtract the sum of its two digits.
Now we have
10x + y - (x + y)
which equals
10x + y - x - y
which, since we are adding and then subtracting y, gives
10x - x
which equals
9x
The answer is always 9 times the first digit.

Notice on the chart the symbol next to all of the following numbers is always 
the same...
9
18
27
36
45
54
63
72
81
90
99

See?

  ----- Original Message ----- 
  From: Rob MacMorran 
  To: geocaching@xxxxxxxxxxxxx 
  Sent: Thursday, February 27, 2003 11:49 PM
  Subject: [GeoStL] Re: NGR: Too Weird


  The number you get from subtracting the sum of the digits of a two-digit 
number from itself will always be divisible by 9.
  In effect you are doing this:
  10x + y - y - x = 9x.
  The 'answer' symbol is always next to every number that is divisible by 9.  
It looks like it is giving you different answers each time because it sneakily 
changes the symbol next to every multiple-of-9-number :) each time you load the 
page.

  What did I win? :)
    ----- Original Message ----- 
    From: Mike Griffin 
    To: geocaching@xxxxxxxxxxxxx 
    Sent: Thursday, February 27, 2003 11:19 PM
    Subject: [GeoStL] NGR: Too Weird


    OK, I will give a dollar to the first person that can figure out how this 
works...

    http://mr-31238.mr.valuehost.co.uk/assets/Flash/psychic.swf


    Mike 

    "Insert useless tagline here"

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