Sudoku

Sudoku is a logic-based,combinatorial number-placement puzzle. The objective is to fill a 9×9 grid with digits so that each column, each row, and each of the nine 3×3 sub-grids that compose the grid (also called "boxes", "blocks", "regions", or "sub-squares") contains all of the digits from 1 to 9. The puzzle setter provides a partially completed grid, which typically has a unique solution.

Sudoku challenges you mind and helps with brain development.

Easy :15 puzzles
Medium: 33 puzzles
Hard: 43 puzzles