SudokuLandD ~ 6,000 original problems ~ – 1.2.2

Total 5000 questions. "15" Children who just remembered numbers until about 6 years old. "20" For beginners, those not familiar with Sudoku. "30" Elementary level, first from here. "40" Intermediate level, general Sampur level. Recommended for those who are used to it. "50" Advanced, to those who are unsatisfactory with difficulty so far.