The CAS Registry Mumber 708-85-0 includes 6 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 3 digits, 7,0 and 8 respectively; the second part has 2 digits, 8 and 5 respectively. Calculate Digit Verification of CAS Registry Number 708-85: (5*7)+(4*0)+(3*8)+(2*8)+(1*5)=80 80 % 10 = 0 So 708-85-0 is a valid CAS Registry Number.