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Chaps,

Try this

Mind reader

Quite clever don't you think. [img]images/graemlins/grin.gif[/img]

Neat indeed.
I think I found the trick.
Will wait though, don't want to post a spoiler.
Eric

Very good. But easy to work out the solution.

[img]images/graemlins/confused.gif[/img]

only did it once or twice correct for me

wot is the solution then?

Uggghhh [img]images/graemlins/spineyes.gif[/img]

I get it.... [img]images/graemlins/smile.gif[/img]

The answer will always be 9, 18, 27, 36, 45, 54, 63, 72, or 81. Each of these always has the same symbol, but the symbol is changed everytime you have a go. Very clever [img]images/graemlins/clap.gif[/img] .

Here is why...

10 = 9, 11 = 9, 12 = 9, 13 = 9, 14 = 9, 15 = 9, 16 = 9, 17 = 9, 18 = 9, 19 = 9
20 = 18, 21 = 18, 22 = 18, 23 = 18, 24 = 18, 25 = 18, 26 = 18, 27 = 18, 28 = 18, 29 = 18
30 = 27, 31 = 27, 32 = 27, 33 = 27, 34 = 27, 35 = 27, 36 = 27, 37 = 27, 38 = 27, 39 = 27
40 = 36, 41 = 36, 42 = 36, 43 = 36, 44 = 36, 45 = 36, 46 = 36, 47 = 36, 48 = 36, 49 = 36
50 = 45, 51 = 45, 52 = 45, 53 = 45, 54 = 45, 55 = 45, 56 = 45, 57 = 45, 58 = 45, 59 = 45
60 = 54, 61 = 54, 62 = 54, 63 = 54, 64 = 54, 65 = 54, 66 = 54, 67 = 54, 68 = 54, 69 = 54
70 = 63, 71 = 63, 72 = 63, 73 = 63, 74 = 63, 75 = 63, 76 = 63, 77 = 63, 78 = 63, 79 = 63
80 = 72, 81 = 72, 82 = 72, 83 = 72, 84 = 72, 85 = 72, 86 = 72, 87 = 72, 88 = 72, 89 = 72
90 = 81, 91 = 81, 92 = 81, 93 = 81, 94 = 81, 95 = 81, 96 = 81, 97 = 81, 98 = 81, 99 = 81

I agree 100% about the multiples of 9 but I think the 46 or 51 are just there to hide a bit more the trick, as I couldn't get 46 or 51 with the rule of substraction.
48 => 36
49 => 36
50 => 45
51 => 45
52 => 45
53 => 45
54 => 45
55 => 45
56 => 45
57 => 45
58 => 45
59 => 45
60 => 54
61 => 54
etc.

Btw, same trick under a groovy layout.

Eric

Forget about the 46 and 51 stuff, they disappeared from the previous posts [img]images/graemlins/sekret.gif[/img]
And the trick could actually work for any number between 1 and 100, not only 10 to 99. Provided 0 was using the same sign as all mutliples of 9.
1=> 0
2=> 0
3=> 0
etc.
and
100=> 99
[img]images/graemlins/wink.gif[/img]
Eric

That's right about the multiple of nine thing.

Think of a two digit number as being two one digit numbers 'a' and 'b'

i.e for 35 a=3 and b=5.

We can express it's actual value as 10*a + b (because the 3 is actually worth 30 or 3 tens)

So doing what it asks which is to sutract from the number the sums of it's digits results in 10*a + b - a - b which is equal to 9*a.

And since a is always an integer (whole number) 9*a must be a multiple of nine.

And yes, the couple of others with the same symbol were just put in to break up the pattern.

-Dan