Using the Einstein relationship: 
Nuclear binding energy = Δmc^2 
number of protons x 1.007825 x 931.5 Me V = X 
number of neutrons x 1.008665 x 931.5 Me V = Y 
Adding up these energies = X + Y 
59.933820 x 931.5 Me V = Z 
Subtract Z from (X+Y)
(X+Y) -Z = Nuclear binding energy 
Divide by the total number of nucleons by the sum of all protons and neutrons in Co 60
(524.807 Me V)/(60 nucleons) = 8.74678 Me V/nucleon.