Quote:
Originally Posted by Ghoulish Delight
Well, if X=the first 3 digits of your phone number and Y=the last 4, then your phone number can be represented as 10000X+Y
So, the operations you perform look like this:
(80X+1)*250+2Y-250
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2
Simplifying the numerator, you get 20000X+250+2Y-250.
The +250 and -250 cancel out, leaving you with 20000X+2Y. Divide that by 2 and you get 10000X+Y, which of course is your phone number.
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My brain hurts just looking at that.