The Times Killer Su Doku: Book 16 (Paperback) (ISBN-13: 9780008342913)

The latest volume in the Killer Su Doku series from the puzzle suppliers to The Times features the highest-quality puzzles with an extra element of arithmetic. The puzzles use the same 9x9 grid as Su Doku but with an added mathematical challenge. The aim is not only to complete every row, column and cube so that it contains the numbers 1-9, it is also necessary to ensure that the outlined cubes add up to the same number as well. With 200 new Moderate, Tricky, Tough and Deadly Killer Su Doku puzzles, there is no chance to ease yourself in with simple puzzles.