The name of the compound above is calcium tetraoxosulphate . The coefficient is 5 means the compound exist as 5 moles. It simply means 5 moles of CaSO4. The natural chemical formula has 1 atom of calcium, 1 atom of sulfur and 4 atom of oxygen.
Since the compound according to the formula exist in 5 mole. The number of atom of Calcium is 1 × 5 = 5 atoms, Sulfur = 1 × 5 = 5 atoms and oxygen = 4 × 5 = 20 atoms.
The total number of atoms of sulfur in the Formula, 5CaSO4 (Calcium sulphate) is 5 atoms.
