All the numbers 1-9 must appear in every row, column and 3×3 section. Numbers inside the dotted cages also must add up to the number in the corner of each cage.
Sudoku is a cross-number crossword that will definitely challenge your brain as well as your patience. (Level of Difficulty on a scale of 1-5: Monday and Tuesday, 1; Wednesday and Saturday, 2; Thursday and Sunday, 3; Friday 4). A classic favorite number puzzle.