Friday, January 02, 2009

New Year's Resolution: Exercise Your Brain

As long as everyone is making New Year's resolutions, I hope you've made one to get more mental exercise. To start you off, here's a challenging "Cross Number Puzzle." The grid above is filled in like a traditional crossword puzzle, except every answer is a three-digit number (100-999) rather than a word. Warning: some of the clues may have you going in circles but there is a unique solution..

Don't worry, you can get around to your other resolutions, like not procrastinating, and going to the gym later. Go sit on the sofa and work on a puzzle instead!

1. 3 Down plus 5 Across
3. One-seventh of 8 Across
5. Half of 14 Across
6. A prime number
8. Seven times 3 Across
10. Twice 7 Down
12. A perfect square
14. 9 Down reversed
15. The sum of its own digits, times thirty-seven
16. A perfect square

1. 13 Down plus 10 Down
2. Average of 9 Down and 14 Across
3. 1 Across minus 5 Across
4. A multiple of three
7. 16 Across minus 1 Across
9. 1 Across plus 5 Across
10. 13 Down plus three hundred
11. 12 Down minus 1 Down
12. Anagram of 4 Down
13. 1 Down minus 10 Down

Stumped or want to check your work? Here's the answer key


  1. Thank you, Blaine, for giving us this place to exercise our minds every week.

  2. Here's a few hints. First obviously no number can start with zero. Second, look at 12A and 16A. Squares will only end with certain digits (e.g. 2 and 3 aren't possible...). That limits your choices for 13D.

    Then there is a relationship between 10D and 13D that affects the values of 13D. Finally look at 1D which is the sum. That should at least get you started.

  3. I didn't get the NYTimes this Sunday, so I did this. I couldn't completely solve this puzzle with a spreadsheet like the mini-sudoku, but a spreadsheet was handy to make number tables which made a trial and error solution possible.
    I stopped building the table when it became apparent that one cell contained a number with the digits 1,8, and 9.

    This past week reminded of the time I visited HMS Warrior in Portsmouth. I asked the Chief what a very shiny piece of brass on a stanchion was for. He said it was to keep the crew busy and out of trouble. Thanks, Chief.

  4. I spent a pleasurable couple of hours solving this clever and nicely constructed puzzle. Was it your creation, Blaine? Either way, thanks for posting it.

  5. Worked on this for hours and hours, with several bad starts but now I've got it! Thanks

  6. please post the solution.. i have tired...

  7. Could you please post the answer again? It's not working anymore and the riddle is driving me crazy ;)

  8. Damn, i'm stuck in the middle. I have to start from beggining, Again ! :o


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