(This post is part of the Genuinely Approachable Sudoku (GAS) series.)
Today’s GAS involves a bit of neighborly addition: Each outside clue shows the sum of the numbers (one or two) around the nine in the row or column.

PDF

or solve online (using SudokuPad)

Theme: Sums Are My Favorite Things

Author/Opus: This is the 98th puzzle from Clover, part of the Genuinely Approachable Sudoku (GAS) team.

Rules: Standard Sudoku rules (insert a number from 1 to 9 into each cell so that no number repeats in any row, column, or bold region). Clues outside the grid indicate the sum of the number(s) immediately adjacent to the 9 in that row or column. For instance, R8C7 and R8C9 sum to 6. If there is only one number next to 9, the outside clue gives the value of that number.

GAS Time Standards (highlight to view): Two party hats (🎩🥳): 7:00; One party hat (🥳): 13:00. All other solvers earn a 🦕: mathy Magnosaurus.

Thomas Hits the GAS (highlight to view): 2:39, with SudokuPad replay file shared as a download for now (requires loading via settings menu with improvements expected before people should use this regularly).

Solution: PDF; solving video with explanation to be added later from GAS team.

Note: Follow this link for other less common variations of Sudoku.

Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our Daily GAS discussion post on the GMPuzzles Discord. Not a member of the Discord? Click this link for basic access.