Compute the normal vector to the surface $(u,v)=(u^2-v^2,u+v,u-v)$ at the point $(3,5)$ and use it to estimate the area of the small patch of the surface $(u,v)$ defined by $3u3\mathrm{.}2,5v5\mathrm{.}1.$

$($Round the answer to four decimal places.$)$