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
Professor's Cube inspection), set by Stanley Chapel of the United States on 27 July 2018 at CubingUSA Nationals 2018. A Filipino TV series from ABS-CBN Entertainment named "Little Big Shots", shows a 10-year old cuber named Franco, who solved a Professor's Cube in 1:47.12 minutes Professor's Cube The Professor's Cube is a combination puzzle, a 5×5×5 version of the Rubik's Cube. It has qualities in common with both the original 3×3×3 Rubik's Cube and the 4×4×4 Rubik's Revenge, and knowing how to solve either can help when working on the 5×5×5 cube. Early versions of the 5×5×5 cube sold at Barnes &