The CAS Registry Mumber 6212-08-4 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 6,2,1 and 2 respectively; the second part has 2 digits, 0 and 8 respectively. Calculate Digit Verification of CAS Registry Number 6212-08: (6*6)+(5*2)+(4*1)+(3*2)+(2*0)+(1*8)=64 64 % 10 = 4 So 6212-08-4 is a valid CAS Registry Number.