Chapter 6.10, Problem 2P

Given $V=x^{2}i+y^{2}j+z^{2}k,$ integrate $V\cdot nd\sigma$ over the whole surface of the cube of side 1 with four of its vertices at $(0,0,0),(0,0,1),(0,1,0),(1,0,0).$ Evaluate the same integral by means of the divergence theorem.