The CAS Registry Mumber 86118-55-0 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,6,1,1 and 8 respectively; the second part has 2 digits, 5 and 5 respectively. Calculate Digit Verification of CAS Registry Number 86118-55: (7*8)+(6*6)+(5*1)+(4*1)+(3*8)+(2*5)+(1*5)=140 140 % 10 = 0 So 86118-55-0 is a valid CAS Registry Number.