Calcudoku Puzzle Books - 400 Easy to Master Puzzles 9x9 (Volume 5)

Calcudoku (also known as "Mathdoku") is a mathematical and logical puzzle loosely similar to Sudoku. The objective is to fill the grid in with the digits 1 through N (where N is the number of rows or columns in the grid) such that: - Each row contains exactly one of each digit. - 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 (