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
Texas State Highway Spur 729 ramp was eventually obliterated, as originally proposed by TxDOT to AASHTO, though its footprint is still visible past the barricades and fencing. Texas State Highway Spur 729 Spur 729 is an approximately state highway spur in King County, Texas. , it was the highest numbered spur route in the Texas state highway system, until the completion of Spur 1966. Spur 729 has an eastern terminus at an at-grade intersection with US 83 near the buildings of the Guthrie Common School District. The short route travels to the west along 6th Street, ending at a barricaded dead end. Spur 729 was