A free program for Android, by Pink Pointer.

What is Sudoku and how do you play it?

Sudoku is a logic-based puzzle in which you must 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 contain all of the digits from 1 to 9. The puzzles are very simple to solve but can be quite challenging to complete in a timely manner.

To get you started, here are the following features of the Sudoku – Classic Puzzle game app:

The app has a variety of different difficulty levels and provides hundreds of puzzles for each. You can save your progress on each puzzle, and undo and redo it as many times as you like. There is also a hint system for beginners, and an input color system for experts. The interface is clean and easy to use and supports both phones and tablets. Google Play Games achievements are also available.