Compute the flux of the field F(x,y,z)=(x,y,z) through the disc defined by x^2+y^2\le25, z=12 and oriented according the superior norm \vec k.

I don't get when it says "oriented according the superior norm \vec k."

By applying the divergence theorem I get 3\displaystyle\int_{0}^{2\pi }{\int_{0}^{5}{\int_{0}^{12}{dz}\,dr}\,d\theta }, but if I try to use \displaystyle\iint_{S}{F\cdot N\,dS}, I don't get the same result.

How to solve this?