The CAS Registry Mumber 86933-28-0 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,6,9,3 and 3 respectively; the second part has 2 digits, 2 and 8 respectively. Calculate Digit Verification of CAS Registry Number 86933-28: (7*8)+(6*6)+(5*9)+(4*3)+(3*3)+(2*2)+(1*8)=170 170 % 10 = 0 So 86933-28-0 is a valid CAS Registry Number.