## Simple puzzle from an app

A forum for good logic/math puzzles.

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gmoff01
Posts: 3
Joined: Wed Feb 04, 2015 8:15 pm UTC

### Simple puzzle from an app

This is a puzzle from Cryptex Challenge, a game on android. I know what the answer is, but I have no idea WHY. I'm guessing you folks should be able to point it out pretty easily.

Its a 5x5 grid, blank space in the center. Grid is as follows:

5 | 4 | 1 | 2 | 5
2 | 4 | 6 | 6 | 2
6 | 3 | ? | 1 | 6
5 | 1 | 9 | 3 | 5
6 | 3 | 2 | 1 | 6

What I've been able to determine:

Spoiler:
I've noticed that if you treat rows 1, 3, & 5 as one group, and rows 2 & 4 as another, the first first two and last two numbers of each row add up to the same totals respective to their group, i.e. (5+4)|(2+5) = (6+3)|(1+6). The same works with the columns. For the rows the difference between these totals is always 2, and for the columns always 4. I'm not sure what if anything to do with this information

Spoiler:
2

HonoreDB
Posts: 161
Joined: Tue Feb 06, 2007 4:32 pm UTC
Contact:

### Re: Simple puzzle from an app

Spoiler:
All 2x2 subgrids add up to 15. Putting 2 in the center preserves that.

gmoff01
Posts: 3
Joined: Wed Feb 04, 2015 8:15 pm UTC

### Re: Simple puzzle from an app

Ah, thats beautiful! Thank you, I'd started down that road, but didnt go granular enough.

Yablo
Posts: 636
Joined: Thu Feb 02, 2012 9:57 am UTC

### Re: Simple puzzle from an app

Apparently I was right, but I didn't put much thought into my guess before making it. What I noticed was:
Spoiler:
For each column, the number in row three was the same as the number in row five; 6-6 , 3-3 , ?-2 , 1-1 , 6-6. That was the pattern I saw, so it was the one that I decided mattered.
If you like Call of Cthulhu and modern government conspiracy, check out my Delta Green thread.

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### Re: Simple puzzle from an app

Yablo wrote:Apparently I was right, but I didn't put much thought into my guess before making it. What I noticed was:
Spoiler:
For each column, the number in row three was the same as the number in row five; 6-6 , 3-3 , ?-2 , 1-1 , 6-6. That was the pattern I saw, so it was the one that I decided mattered.

Spoiler:
The fact that this method works feels like a weakness in the puzzle design. If the bottom row was, for example, 7-2-3-0-7, it wouldn't be possible to take this shortcut.