$f(x,y) = 5 - \frac{1}{10}(x^2+y^2)$, $R = [0,5]\times[0,5]$
Volume $= \iint_R f(x,y)\,dA = \frac{250}{3} = 83.33333\dots$
Riemann approximation
≈
46.8750
Number of slices: