Ideas for improving my Sudoku game [closed]

1. What is the 45 rule in Sudoku?
2. What is the average time to finish a Sudoku?

What is the 45 rule in Sudoku?

The Rule of 45

All the numbers in a given row, column or nonet should add up to 45. This rule can also be used smaller puzzles: the number is 21 for a 6x6 puzzle and 10 for a 4x4 puzzle. Take a look at the Killer Sudoku grid below.

What is the average time to finish a Sudoku?

It is believed that the average Sudoku player spends approximately 20 minutes solving a typical Sudoku puzzle. For very hard puzzles, that number can be much higher. While the game itself can be challenging and complex, several strategies can be used successfully to find the solution.