(This post is part of the Genuinely Approachable Sudoku (GAS) series.)
45… The measure of the acute angles in an isosceles right triangle. The atomic number of rhodium. The cost in cents of a US postage stamp in 2012. Oh, and the sum of the numbers 1 to 9….
Wait, 4 AND 5, not 45? Those are the numbers you’ll be counting to in this Count Different Sudoku.

PDF

or solve online (using SudokuPad)

Theme: 45

Author/Opus: This is the 173rd 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). The number in each domino-shaped cage indicates how many unique values appear in the surrounding cells (i.e., all adjacent and diagonally neighboring cells to the cage, as many as 10 cells when the cage is in the interior).

GAS Time Standards (highlight to view): Two party hats (🎩🥳): 6:00; One party hat (🥳): 11:00. All other solvers earn a 🦕: secret Seitaad.

Thomas Hits the GAS (highlight to view): 1:56, 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

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.