How many different Sudoku solutions?
Sometimes people ask us: “how many different Sudoku puzzles are there?”. To answer this we need to understand that each Sudoku puzzle gives just one unique solution grid. We can say that two Sudoku puzzles are the same if they resulted in the same solution. So, a similar question is: “how many different complete Sudoku solutions are possible?”. First of all, let’s first look at a much simpler grid, namely the 2×2 Sudoku with the numbers 1 to 4. The three rules for solving Sudoku still apply: The row rule (place the numbers 1 – 4 in each row), the column rule (place the numbers 1 to 4 in each column) and the subsquare rule (place the numbers 1 – 4 in each subsquare). On the first row, count how many different ways can we place the numbers 1, 2, 3 and 4 in the row. In the first square, we have four numbers to choose from. In the second square, we have only three numbers to choose from, as we have already placed the previous square. We have two choices for the third square and only one ch
