Cube (algebra) however, easy to show that most numbers are not perfect cubes because "all" perfect cubes must have digital root 1, 8 or 9. That is their values modulo 9 may be only −1, 1 and 0. Moreover, the digital root of any number's cube can be determined by the remainder the number gives when divided by 3: Every positive integer can be written as the sum of nine (or fewer) positive cubes. This upper limit of nine cubes cannot be reduced because, for example, 23 cannot be written as the sum of fewer than nine positive cubes: The equation has
Cube Zero forest with her daughter. Rains wakes up in the Cube and meets the other occupants: one of them, Robert Haskell, has the same tattoo on his forehead as the soldier who captured her. However, Haskell, like everyone else, only knows his own name and has no recollection of his former life or how he got there. According to what Wynn and Dodd know, everyone in the Cube faced a death sentence and volunteered to partake in psychological experiments instead. Rains' consent form, however, is not found in her file. The captives venture through the Cube, testing each room for traps