
New Puzzle Challenges Math Skills - jaydub
http://www.nytimes.com/2009/02/09/arts/09ken.html?hp
======
mdonahoe
I got really addicted to KenKen, but I couldn't find a good source of
unlimited puzzles, so I made my own puzzle generator

<http://mattdonahoe.com/numnum/print>

It was a quick thing I did one night. No error/win checking and only supports
multiplication.

Later I found <http://www.webkendoku.com/> but I still use my iphone version
<http://mattdonahoe.com/numnum/iphone>

------
mshafrir
From the article: "¶Look for cages whose target numbers are unusually high or
low for their number of squares. Often these have unique answers. For example,
in a six-by-six puzzle, two squares with a sum of 11 must be filled with 5 and
6, in some order. Three squares with a product of 10 must be 1, 2 and 5."

Why must two squares with a sum of 11 be filled with 5 and 6?

~~~
req2
A 6x6 puzzle runs from 1-6.

------
Dilpil
The real test is coding the solver, or, for the theorists, proving the lower
bounds runtime for such a solver.

------
michael_dorfman
Sorry, but I'm not getting it. If there are two boxes together with the label
"6x", does that mean that six times the first square should equal the second
square? If so, how are we to interpret the 120x? If not, what's the meaning?

~~~
FalconNL
From what I understand you're supposed to get the result (in your example 6)
by combining the cells in that box with the given operator (in this case
times).

So a "6x" box with two cells results in (1 and 6) or (2 and 3), since those
are the only products that result in 6. Likewise, "7+" with three squares can
only be (1, 2 and 4).

~~~
gjm11
7+ could also be 1,3,3 or 3,2,2 if the box is L-shaped so that the equal
numbers don't go in the same row or column.

