Sudoku Challenge: 200 Fiendish Sudoku Puzzles With a Twist

In Sudoku Challenge, you fill in the puzzles with the usual rules, but when the grid is complete, you then use the clue numbers to work out how to calculate the challenge number. 

Unique, fun, and interactive this collection of brain-teasing puzzles, can be played offline and will keep you entertained for hours and hours.

Whether you are looking for puzzle practiceto train your brain, or seeking a screen-free offline alternative to online puzzles, or a sudoku challenge like no other this collection will have you enthralled.