Decent fitness and energy for the brain. Calcudoku - this is a mathematical and logical puzzle. It is necessary to fill the grid with numbers so that in each line and in each column they are not repeated. The number in the corner of each selected block is the result of an arithmetic operation on the digits in this block. The numbers inside the block can be repeated. All signs of mathematical signs are hidden. The puzzle can be called Square Wisdom, Kendoku. Jigsaw Even - Odd Puzzles X Diagonal - The puzzle may contain regions of arbitrary shape; such sudoku called geometric or curly ("Jigsaw Sudoku", "Geometry Sudoku", "Irregular Sudoku", "Kikagaku Nanpure"). The puzzle contains information about the parity or odd numbers in the cells. In the cells with gray squares are even numbers. In this puzzle, the main diagonals of the square contain numbers from 1 to 9. 50 maximally challenging Calcudoku sudoku puzzle easy levels. 50 maximally challenging Calcudoku sudoku puzzle medium levels. 50 maximally challenging Calcudoku sudoku puzzle hard levels. 50 maximally challenging Calcudoku sudoku puzzle very hard levels. 50 Jigsaw Odd Puzzles "X" Diagonal sudoku puzzle easy levels. 50 Jigsaw Odd Puzzles "X" Diagonal sudoku puzzle medium levels. 50 Jigsaw Odd Puzzles "X" Diagonal sudoku puzzle hard levels. 50 Jigsaw Odd Puzzles "X" Diagonal sudoku puzzle very hard levels. - unique puzzles. + 250 sudokus difficult level that can be downloaded and printed. + 250 maze puzzles that can be downloaded and printed. - only 1 verified solution. - all answers are at the end of the book. - exclusive puzzles. - a link to the surprise is at the end of the book. An excellent book for free time and mind exploration. I hope you enjoy the book. Best regards, Basford Holmes