Sudoku-Teacher for iOS

Sudoku is a reasoning game that originated in Switzerland. The number puzzle was later developed in the United States and flourished in Japan. The Sudoku board is a nine-square, and each square is divided into nine small grids. In these eighty-one grids, given certain known numbers and problem-solving conditions, use logic and reasoning, and fill in the other spaces with 1- The number 9. Make each number 1-9 appear only once in each row, column, and sub-grids.