Re-Gift Robin: How does it work?

Have you ever used Re-Gift Robin and wondered how it works?

First try it out (http://www.regiftable.com), then view the proof below -



The trick lies in the number 9

All of the items corresponding with a multiple of nine on the grid are the same re-gift...

Here's the simple mathematical proof:


f = first digit of the number

s = second digit of the number

= (10*f) + (1*s) - f - s

= 10 * f - f

= 9 * f


The website randomly changes the item every time, so that it seems like they're playing a Jedi mind trick on you...

But don't be fooled! ;-)