Flash Mind Reader Secrets Revealed!

"Why does Andy Naughton's Flash Mind Reader work?!"

Quite some time ago, when the search engine Google was not quite as popular as it is now, I included it on a list-of-links page on this site. I said something like it "probably has some kind of mind-reading algorithm happening" and assumed that, even more so than other parts of the site, the page was rarely looked at. At some point, I found myself with nothing better to do than muse over the access logs of my site, and to my bemusement, found that this links page was getting a large number of search engine referrals because of my use of the phrase mind reading algorithm. Intrigued, I added a request that anyone arriving at the page by such a method might email to tell me, for curiosity's sake, just what the hell they were looking for...

It didn't take long. (Thanks, Dean!).

So I decided to put people out of the misery of their fruitless searches, and give them the information that they were looking for!

This Flash Mind Reader, you may be astonished to know, does NOT read your mind! So you can stop freaking out right now, and for God's sake take that aluminium foil off your head, you just look silly.

Now, pay attention:

Take all the numbers from 10 to 19. Do the math that is asked of you in the FMR, taking each of these in turn as your starting-number (the number you're thinking of). You'll see that each time, the answer is 9. This is simple: Every time you advance one number from 10, the "add two digits" bit increases by one, so the "subtract from the number you first thought of" decreases the end result by one, therby leaving the result always the same: nine.

  10:   10 - (1+0)  =  10 - 1  =  9
  11:   11 - (1+1)  =  11 - 2  =  9  

Similarly, the numbers 20 to 29 give you 18, 30 to 39 give you 27, etc.. Spot the pattern? It's multiples of nine! Take a look at the FMR page again - you'll notice that each multiple of nine has the same symbol. And this symbol will be the one that is shown when you click on the glass ball.

Here it is in algebraic form:

Take a two-digit number "xy", where x is the first digit and y is the second. The value of the number is therefore 10x+y.

     10x + y - ( x + y )
  =  10x + y - x - y
  =  9x

... So the number you end up with is simply 9x, where x is the first digit of your two-digit number. The second digit has no bearing.

I have to say that I am disappointed that so many people, instead of taking the time to work this out for themselves (you would have spotted the multiples-of-nine pattern pretty quickly, I reckon, even without great math skills), just went straight to a search engine and tried to find an actual mind reading algorithm! I get hits to my site from this search string more than once a day! -- Yet again my faith in the human race takes a beating. :-(