The CAS Registry Mumber 86611-27-0 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,6,6,1 and 1 respectively; the second part has 2 digits, 2 and 7 respectively. Calculate Digit Verification of CAS Registry Number 86611-27: (7*8)+(6*6)+(5*6)+(4*1)+(3*1)+(2*2)+(1*7)=140 140 % 10 = 0 So 86611-27-0 is a valid CAS Registry Number.