In face centred cubic lattice of a metal solid how many atoms make contribution to each unit cell, to result a contribution of four atoms ?

In fcc lattice atoms are present at all g corners, and at all six face. centres making a total contribution of 4 atoms per unit cell

$\left(8\times \frac{1}{8}\right)+\left(6\times \frac{1}{2}\right)=1+3=4$