The CAS Registry Mumber 86221-07-0 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,6,2,2 and 1 respectively; the second part has 2 digits, 0 and 7 respectively. Calculate Digit Verification of CAS Registry Number 86221-07: (7*8)+(6*6)+(5*2)+(4*2)+(3*1)+(2*0)+(1*7)=120 120 % 10 = 0 So 86221-07-0 is a valid CAS Registry Number.