Sudoku Solver (in Excel, with no Macros)

Remember when these fun and sometimes frustrating mathematical puzzles swept the globe? Too young?
Lucky you!

Ready to enter data

A sudoku is straight-forward. Given a partially-filled grid, you use logic to place every number 1 - 9 in each row, column, and block of nine squares in the Soduku, exactly once. No repetition is allowed.

This sounded like a mathematical puzzle to Ian! One lazy afternoon, he formulated a spreadsheet that used Deduction, Elimination and Induction to help fill squares in.
Partially filled

And repetition, to cycle through to solve the puzzle.

Ian almost missed out on a role as a business analyst in the mid-2000's since the recruiter didn't see strong enough Excel emphasis on his CV back then. He sent through this spreadsheet, got the interview and landed the job.

All thanks to that lazy afternoon.