Sudoku Number Math Puzzle

Welcome to Free Sudoku puzzle game. Thousands of sudoku puzzles to solve. Let's play and train your brain daily.
Sudoku (originally called Number Place) is a logic-based, combinatorial number-placement puzzle.
HOW TO PLAY
• Mission is to complete the puzzle, you must fill each square on the grid with 1-9 numbers. The numbers 1-9 should appear exactly once in each row, column, and box 3 x 3.

FEATURES:
• 4 different modes to select has a unique solution (Easy, Medium, Hard And Very Hard)
• Intelligent Hint system that you can use when you stuck
• Unlimited undo/redo
• 100% free and offline sudoku game
• Automatic Save and Resume Every time.
Have fun with my Sudoku number game.

Reference sources:
https://freesound.org/people/tim.kahn/sounds/43448/
https://freesound.org/people/Ch0cchi/sounds/15348/
https://freesound.org/people/FxKid2/sounds/367627/
https://freesound.org/people/themusicalnomad/sounds/253886/