About Book Want to exercise your brainpower and have fun at the same time? Then this book is for you. This book introduces you to the amazing world of Calcudoku puzzles. It will help you understand the rules of this puzzle. This book is perfect for players of all ages. You will find 200 exciting puzzles, for professionals. HOW TO PLAY The objective is to fill the grid in with the digits 1 through 9 (where 9 is the number of rows or columns in the grid) such that: Each column contains exactly one of each digit. Each bold-outlined group of cells (block) contains digits which achieve the specified result using the specified mathematical operation: addition (+), subtraction (-), multiplication (?), and division (?). No single number can repeat in any row or column. As Calcudoku belongs to the same class of puzzles as Sudoku the puzzle can demonstrate a wide spectrum of relative difficulty. The grade is determined by a combination of opportunities to solve at each stage and the difficulty of the strategy that grants each solution. Puzzles almost like Killer Sudoku, but unlike Killer Sudoku, digits may repeat within a block.