SAT Sudoku (Quads and Anti-Quads)
(Published on 27. August 2021, 13:00 by RockyRoer)
Just in time for SAT season! Good luck to my students that are taking it this weekend! Some friendly test taking strategies and reminders -- you don't have to answer the questions in order -- sometimes you should skip a question and come back to it at the end if there's time. Unlike the real SAT -- guesses are penalized in this puzzle! For maximum fun and the most authentic test-taking experience, print this and fill in the correct bubbles with a #2 pencil and give yourself exactly 25 minutes. No calculators allowed!
The Rules:
- Normal sudoku rules apply (fill each row, column, and 3x3 rectangle with digits from 1 to 9 with no repeats).
- Quads/Anti-Quads: Each region contains four circles. Exactly one is a correct quad: the number(s) inside must appear somewhere in the surrounding four cells. The other three are anti-quads: the number(s) inside CAN NOT appear in the surrounding four cells. The solver must determine which are which.
The Puzzle:
Missed the smaller SAT Test Prep puzzles?
- 6x6 (2 bubbles each - 1 is correct) https://f-puzzles.com/?id=ygjshv5e
- 8x8 (3 bubbles each - 1 is correct) https://f-puzzles.com/?id=ygyytjxw
Solution code: Let the options in each box be labeled A, B, C, D. List the correct quad for each box 1-9 followed by digits in row 1. (9 letters and 9 numbers) (e.g. ABDCDDADB189245367)
Comments
on 29. July 2023, 10:07 by dennischen
These are some really clever clue choices, and it's remarkable that the puzzle not only looks but also solves really nice.
on 4. September 2021, 04:54 by theParad0x
beautiful construction. The interactions were quite something!
on 3. September 2021, 23:08 by Orpheus
What great fun! It almost makes me miss standardized tests... almost.
REPLY: well, I can say that writing this puzzle was way more fun than proctoring the last exam. Nothing more boring than standing around watching students fill in bubbles.
on 28. August 2021, 23:13 by RootsInWermland
Really fun puzzle to solve with some tricky stuff. Interesting how powerful a quad becomes when you find out that one is certainly right or certainly wrong. Thanks!
REPLY: Glad you enjoyed it! I think I found the anti-quads even more powerful than the regular quads. Be sure to try the smaller puzzles if you enjoyed this -- the different shaped regions makes for slightly different logic that's also fun.
on 28. August 2021, 06:44 by panthchesh
Thanks for the puzzle! That was fun :)
on 27. August 2021, 19:35 by henrypijames
Die 0 stellt eine Ziffer dar, die im klassischen (und klassisch-basierten) Sudoku illegal ist. :D
on 27. August 2021, 19:13 by SKORP17
wass soll den die 0 darstellen?
REPLY: since zero isn’t allowed in this sudoku, I think any circle that contains a zero will necessarily be impossible to fulfill… ;-)
on 27. August 2021, 16:38 by RockyRoer
updated typo in solution code
on 27. August 2021, 16:30 by henrypijames
Please check solution code - mine is being rejected, but I'm sure it's right. Also, better spell out how the ABCD labels are assigned.
3¼ stars difficulty.
REPLY: I had a typo in the letters. Should be fixed now. If you are still having errors, feel free to submit your solution code in a hidden comment and I can confirm.
on 27. August 2021, 14:10 by henrypijames
It bothers me that some clues read 81 instead of 18. Since the order doesn't matter (or does it?), it should be ascending by default.
REPLY: The order doesn't matter -- but is purely cosmetic. The choice of 81 instead of 18, say in box 3, is intentional as the options 3, 9, 27 and 81 are all powers of 3. And in box 9, they are all multiples of 9.
