or solve online (using our beta test of Penpa-Edit tools)
Theme: Plus and Minuses
Author/Opus: This is the 1st puzzle from guest contributor Michael Rios.
Rules: Standard Sudoku rules. Also, each row, column and bold region must contain two negative digits. The sum of the positive and negative digits in each cage must equal the value given in the upper-left corner of that cage. Digits (ignoring sign) cannot repeat inside a cage.
See also this example:
Difficulty: 5 stars
Time Standards (highlight to view): Grandmaster = 15:30, Master = 26:00, Expert = 52:00
Note: Follow this link for more Killer Sudoku and this link for classic Sudoku. More Sudoku puzzles can be found in The Art of Sudoku, The Art of Sudoku 2 and in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli.