These printable sudoku puzzles are four different levels of difficulty. You want to start with the easy ones, but if you're an expert, you can skip to the extra hard puzzles. The post 20 Printable ...

Back in 2020, Reddit user /u/KrakenOfLakeZurich created a Sudoku solver in Microsoft Excel. It only uses formulae and conditional formatting, and it's available for both Excel and LibreOffice Calc.