Cross-number puzzle for 2008

plutoman · 2008-01-06 21:07:08

Hi all,

I've been browsing the puzzles on this forum and thought you might like to have a look at this one from my new puzzle website:

http://www.plutopuzzles.com/puzzles/maelstrom/maelstrom2008.htm

It is supposed to be tricky but not impossible, so if someone could have a go at it, and let me know what they think, I'd really appreciate it.

There are plenty more puzzles on the site for you to tackle if you wish.

Thanks a lot.

John E. Franklin · 2008-01-07 07:51:36

That looks like fun. I think it starts with the 251, I'll keep going!!!

Please tell me there are no negative numbers?

This is fun if you like to try lots of numbers.

Also "251 (number)" in wikipedia helped.

Last edited by John E. Franklin (2008-01-07 09:08:12)

plutoman · 2008-01-07 18:02:17

No there aren't any negative numbers in the solution! That would be particularly sneaky, and didn't actually cross my mind when I wrote these puzzles.

Yes, 251 is certainly a good place to start. Had a look that Wikipedia article - can't say I'd ever heard of sexy primes before!

Keep going!

mathsyperson · 2008-01-08 01:41:49

Interesting that you should be talking of double 4's, because 44 was the first answer I filled in.
I've now got five answers in total, so I'm not quite as far as John but I've made a reasonable start.

mathsyperson · 2008-01-08 05:26:05

...And solved.
It looks like I did it in a completely different order to John, because he's halfway through and hasn't done the one I started with. I also did the clues featured in your 'Puzzle Info' box very near to the end.

Very enjoyable puzzle, overall. I like how it can be completely solved with logic and perseverance.
I also like how it's rotationally symmetrical, but that might just be me.

Edit: And now also solved the other two Maelstrom puzzles as well.
More would be very welcome.

plutoman · 2008-01-08 12:28:15

Mathsyperson,

Well done! Glad you enjoyed the puzzle. The intention was that it could be solved with logic and perseverance rather than just trial and error.

In fact making a grid that works isn't that easy. As well as making it rotationallly symmetrical (like crosswords you see in newspapers) I also have to ensure that there are 26 answers in the grid (one for each letter of the alphabet) and that there are no ambiguous across/down answers.

plutoman · 2008-01-25 17:55:30

Mathsyperson (and whoever else might be interested),

I've just uploaded another couple of Maelstrom puzzles (nos. 4 and 5) to my web page:
Click here

If it was up to me, I'd be spending far more time creating new puzzles than I currently am. Still, I hope to update the site with new puzzles more frequently from now on, so keep checking!

mathsyperson · 2008-01-26 01:30:54

Awesome!
That was impeccably timed (for me, at least) because I'm currently in that glorious gap between the end of exams and the start of lectures where I have absolutely nothing that I'm supposed to be doing.

John E. Franklin · 2008-01-26 11:27:34

Puz#5 is too hard for me because the possibilities are in the hundreds for so many numbers.
Like sometimes you narrow it down between 32 and 99, or 100 to 316.
Maybe if you gave like ten or fifteen more equations that tied the whole thing up.
Like start combining pairs and triplets of answers in various ways, and
give some hints about them. Like say something about the absolute value
of the difference of R and V. If you add all the digits in some numbers it is
an odd number, or between 4 and 9, etc.

mathsyperson · 2008-01-26 13:04:33

Just finished puzzle#4, and I think there are three solutions.

Edit: And now #5 too. That one was definitely harder than the rest!

plutoman · 2008-01-27 12:27:05

Yep, you've got me there with number 4. That's probably the hardest thing for me - making sure I haven't overlooked any possible solutions. Multiple solutions don't invalidate the puzzle (there's nothing in the rules stipulating a single solution) but people tend to prefer a unique solution. I remember for instance in 2005 there was some controversy in the UK when Sudoku puzzles appeared in (I think) the Telegraph with multiple solutions. Maybe if my puzzles provoke controversy that's no bad thing (!), but I'll certainly be aiming for a unique solution in future.

Anyway, I'd agree puzzle 5 is at the tricky end of the spectrum, and I'm pretty sure that one does have a unique solution; it looks like you've found it, so well done!

John: firstly these puzzles aren't meant to be easy. There are subtle hints to that effect on the Maelstrom web page. I try to make the puzzles as elegant as possible, which generally means that you'll need to use all the clues to arrive at the solution. However, I will try to vary the difficulty level, so that some puzzles are considerably easier than number 5! I also hope to produce puzzles with clues like "A is prime", "(B+C) is a cube" in future.

plutoman · 2008-03-12 21:28:21

Hello again,

Well I made a sneaky alteration to number 4 in the end, forcing a unique solution to the puzzle.
There are now nine Maelstrom puzzles on my site (which should keep you going for a while). For one that's slightly different, have a go at this one.

Any feedback would be appreciated. Also, feel free to have a go at some of the other puzzles on my site. Good luck!

Math Is Fun Forum

#1 2008-01-06 21:07:08

Cross-number puzzle for 2008

#2 2008-01-07 07:51:36

Re: Cross-number puzzle for 2008

#3 2008-01-07 18:02:17

Re: Cross-number puzzle for 2008

#4 2008-01-08 01:41:49

Re: Cross-number puzzle for 2008

#5 2008-01-08 05:26:05

Re: Cross-number puzzle for 2008

#6 2008-01-08 12:28:15

Re: Cross-number puzzle for 2008

#7 2008-01-25 17:55:30

Re: Cross-number puzzle for 2008

#8 2008-01-26 01:30:54

Re: Cross-number puzzle for 2008

#9 2008-01-26 11:27:34

Re: Cross-number puzzle for 2008

#10 2008-01-26 13:04:33

Re: Cross-number puzzle for 2008

#11 2008-01-27 12:27:05

Re: Cross-number puzzle for 2008

#12 2008-03-12 21:28:21

Re: Cross-number puzzle for 2008

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