Calcudoku Plus Puzzle Books - 400 Easy to Master Puzzles 6x6 (Volume 7)

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 (+).

• Unlike Killer Sudoku, digits may repeat within a block.