OK.. its late and between you and Lord Cronos, you guys will have to split the dollar.. I did not catch that they were changing. It looks like you guys live for this stuff... I knew I could get an answer here.. I guess if both of you will be at the Picnic, I will have to buy you a coke. Mike "Insert useless tagline here" ----- Original Message ----- From: Rob MacMorran To: geocaching@xxxxxxxxxxxxx Sent: Thursday, February 27, 2003 11:55 PM Subject: [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"