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Old 08-26-2016, 05:15 PM
Indistinguishable Indistinguishable is offline
Join Date: Apr 2007
Posts: 10,512
Well, these are tricks to impress children, primarily, right? Illustrations of algebra to entice those who haven't yet thought about it.

Incidentally, even if it wasn't so smooth, you would imagine any series of steps of this sort could be undone easily enough: take your age, add 2, multiply it by 8, subtract 3, square it, reverse the digits, and tell me what you got. Ok, now I'll deduce your age: I'll reverse the digits, take the square root, add 3, divide by 8, and subtract 2. That sort of thing.

(Hell, since there's only so many ages someone (and particularly a child) might reasonably have, I may as well just invent any old random complicated but injective function from input ages to output whatevers and just memorize the mapping back from outputs to inputs.)

Last edited by Indistinguishable; 08-26-2016 at 05:18 PM.