The latest volume in the hugely popular Killer Su Doku series from the puzzle suppliers to The Times featuring the highest-quality puzzles with an extra element of arithmetic This addition to the successful Times Killer Su Doku series will test your skills to the limit adding the challenge of arithmetic & taking Su Doku to a new & even deadlier level of difficulty The puzzles use the same 9x 9 grid as Su Doku but with an added mathematical challenge The aim is not only to complete every row column & 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 & Deadly Killer Su Doku puzzles there is no chance to ease yourself in with simple puzzles For those who like to live dangerously & pushbeyond their mental comfort zone steel yourself for The Times' next terribly tough instalment