Daily Calcudoku 2025: A Puzzle a Day for all 365 Days of the Year

Keep your brain active every day, from 1st January to 31st December!
From ‘Britain’s King of Puzzles’ (The Sun) comes this bumper book of calcudoku puzzles - also known as KenKen™ or mathdoku - with a brand new difficulty-rated challenge for every day of 2025.

All of the calcudoku puzzles get harder throughout each week, with Monday being the easiest day and Sunday being the trickiest. Individually dated for each day of the year, each puzzle provides a graded workout to help keep the mind active and reduce stress.

To complete each puzzle, simply place a digit from 1 to 5, 6, 7, 8 or 9 (depending upon the grid size) into every empty square, so that no digit repeats in any of the rows or columns. Also, the value at the top-left of each bold-lined region must result when all the numbers in that region have the given operation (+, –, ×, ÷) applied between them.

• 366 unique calcudoku puzzles, dated for every day of the year, with a bonus puzzle for 1st January 2026

• Difficulty grading for every puzzle, from very easy through to very hard

• Seven different difficulty levels, one for each day of the week

• Clear, simple instructions

• Full solutions at the back

Daily Calcudoku 2025 is the perfect gift for all calcudoku fans, as well as sudoku or killer sudoku solvers looking for something new, from beginners through to seasoned solvers.