The CAS Registry Mumber 108005-08-9 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,8,0,0 and 5 respectively; the second part has 2 digits, 0 and 8 respectively. Calculate Digit Verification of CAS Registry Number 108005-08: (8*1)+(7*0)+(6*8)+(5*0)+(4*0)+(3*5)+(2*0)+(1*8)=79 79 % 10 = 9 So 108005-08-9 is a valid CAS Registry Number.