For those who like to live dangerously and push beyond their mental comfort zone, the toughest collection yet has an added math challenge taking Su Doku to an even deadlier level of
difficulty
The seventh and toughest addition to the successful Times Killer Su Doku series will test puzzlers' skills to the limit, using the same 9x9 grid as normal 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 digits one through nine, it is also necessary to ensure that the outlined
cubes add up to the same number as well. With 150 new "tough" and "deadly killer" puzzles, there is no chance to ease in with easy puzzles.
