# Thread: Does anyone know how they do the Fido Puzzle?

1. YahooHoo
Join Date
Aug 2007
Posts
4

## Does anyone know how they do the Fido Puzzle?

An amazing puzzle

Take your time and follow the instructions. It's neat!!!

After reading each window, click on the boy in the lower right corner. In the last window, type in your numbers in the white box using the keyboard (there is NO curser). You will be amazed....and no, I sure don't know how it's done. The answer appears on the boy's t-shirt.

2. YahooHoo
Join Date
Aug 2007
Posts
1
wow, that's weird. how did he do that? thank you for sharing. by the way, here's the link, your's isn't right:
http://digicc.com/fido/

3. YahooHoo
Join Date
Aug 2007
Posts
1
What I think happens is that it has specific answers set up for the digits you enter in the final box. For example, I ended up with 540. I circled the five. I entered 4 and 0. It correctly responded with 5. I did it again with 0 and 4. it still responded with 5. the only possible way that it works would be that it knows that when their is a four and zero, there has to be a five as the other digit. To do this, it must have a certain math formula or program in it.
Yep, just checked
here it is:
WHY THE FIDO PUZZLE WORKS

The key lies in a characteristic of the number 9. If you transpose the digits in a number and subtract the smaller number from the larger, the difference is always evenly divisible by 9.

Example 1
4321 rearranged to 1423
4321 minus 1423 = 2898
I choose to circle the 9, leaving the numbers 2, 8 & 8 to be typed in.
The only number that may be added to the sequence 2+8+8 and be divisible evenly by 9 is 9 (the digit I circled). [2+8+8+9=27]

Example 2
6734 rearranged to 7346
7346 minus 6734 = 612
I choose to circle the 6, leaving the numbers 1 & 2 to be typed in.
The only number that may be added to the sequence 1+2 and be divisible evenly by 9 is 6 (the digit I circled). [1+2+6=9]

Example 3
578 rearranged to 857
857 minus 578 = 279
I choose to circle the 2, leaving the numbers 7 & 9 to be typed in.
The only number that may be added to the sequence 7+9 and be divisible evenly by 9 is 2 (the digit I circled). [7+9+2=18]

The designer has programmed the puzzle to do the math so your computer has no problem supplying the 'missing' number.

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