The CAS Registry Mumber 676133-67-8 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 6,7,6,1,3 and 3 respectively; the second part has 2 digits, 6 and 7 respectively. Calculate Digit Verification of CAS Registry Number 676133-67: (8*6)+(7*7)+(6*6)+(5*1)+(4*3)+(3*3)+(2*6)+(1*7)=178 178 % 10 = 8 So 676133-67-8 is a valid CAS Registry Number.