Present Tens
(Published on 19. November 2025, 17:43 by Nell Gwyn)
- Balanced Sudoku: Place the numbers -4 to 4 once each in every row, column and 3x3 box.
- Arrow: Numbers along an arrow must sum to the number in the circle or oval. Two-digit numbers are written in the balanced nonary numeral system (just multiply the first digit by 9 and add the second digit), left to right or top to bottom.
- Ten Lines: Each reddish line must be split into one or more non-overlapping segments, each of which sums to exactly 10.
SudokuPad (for the answer check, enter the absolute value of each digit)
Penpa (no answer check embedded, but has more flexible notation options)
Solution code: Row 9, with a "-" in front of the negative digits (e.g. -42403-31-2-1
Comments
on 21. November 2025, 07:05 by Nell Gwyn
I clarified the numeral system in the rules. The puzzle itself is unchanged.
on 20. November 2025, 20:08 by dkfan9
Great puzzle! Fun number system. My only critique would be asking for a clearer description of the number system, in the form of an example. It took me a bit of research to determine how a negative digit is handled, and to understand what is meant by "multiplied by 9". Web search didn't turn up results for balanced nonary system but I was able to extrapolate from balanced ternary. But now I know, and I'm always happy to learn. For me, I would understand better if it was stated something like "the first digit is the "nines place" as opposed to the tens place in the standard decimal number system", and an example could be "2 -3 in bal nonary = 15 in decimal"
~~
It might be easier to clarify with "Just multiply the first digit by 9 and add the second digit." I'll do that. - Nell
on 19. November 2025, 20:28 by Manta-Ray
Great puzzle! On the face of it this looks really complicated but once you get into it the solve flows really nicely, thanks!
on 19. November 2025, 18:24 by ThePedallingPianist
Don't be put off by scary long words like "balanced nonary numeral system" - this is actually a very approachable, generously clued, and most importantly fun puzzle! Lovely idea :)
