The CAS Registry Mumber 474-05-5 includes 6 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 3 digits, 4,7 and 4 respectively; the second part has 2 digits, 0 and 5 respectively. Calculate Digit Verification of CAS Registry Number 474-05: (5*4)+(4*7)+(3*4)+(2*0)+(1*5)=65 65 % 10 = 5 So 474-05-5 is a valid CAS Registry Number.