Calcudoku

Calcudoku, also known as Mathdoku, KenKen, or Square Wisdom, is a logic puzzle. The objective is to fill a grid with numbers such that certain conditions are met. The grid is divided into cages, each marked with a number and an arithmetic operation. The numbers within each cage must combine using the specified operation to produce the given number. Additionally, no number can be repeated in any row or column, similar to Sudoku. The size of the grid can vary, with common sizes being 4x4, 6x6, or 9x9.

The rules are straightforward but lead to complex problem-solving. For a 4x4 grid, the numbers used are typically 1, 2, 3, and 4. For larger grids, the numbers used correspond to the grid dimensions. The arithmetic operations commonly found are addition, subtraction, multiplication, and division. Subtraction and division cages have a specific order in mind: the larger number must be placed before the smaller number for the operation to result in the target value. For example, a cage with the number 3 and the subtraction symbol would require the numbers 4 and 1 to be placed within it, as 4-1=3. A cage with the number 2 and the division symbol would require 4 and 2, as 4/2=2.

Calcudoku puzzles are designed for players of all skill levels, with easier puzzles featuring smaller grids and simpler operations, and more challenging puzzles increasing the grid size and complexity of cage combinations. The puzzle requires logical deduction, arithmetic skills, and spatial reasoning to solve. It is a popular brain-training activity found in newspapers, books, and online platforms.