Free Sudoku: Sudoku Puzzles

The objective of Free Sudoku game is to enter a digit from one through nine in each puzzle cell, in such a way that each horizontal row, each vertical column and each sub-grid or region of the puzzle contains each digit exactly once.
Solving a sudoku puzzle is simple it does not require knowledge of mathematics.
Free Sudoku has three levels of difficulty: easy, medium and hard.
Free Sudoku if a free game.