Install ksudoku by entering the following commands in the terminal:
sudo apt update sudo apt install ksudoku
Description:
Sudoku puzzle game and solver
KSudoku is a Sudoku game and solver, supporting a range of 2D and 3D Sudoku variants. In addition to playing Sudoku, it can print Sudoku puzzle sheets and find the solution to any Sudoku puzzle. . This package is part of the KDE games module.
Homepage: http://games.kde.org/
Version: 4:17.12.3-0ubuntu2
Section: universe/games