The CAS Registry Mumber 108005-04-5 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 4 respectively. Calculate Digit Verification of CAS Registry Number 108005-04: (8*1)+(7*0)+(6*8)+(5*0)+(4*0)+(3*5)+(2*0)+(1*4)=75 75 % 10 = 5 So 108005-04-5 is a valid CAS Registry Number.