The CAS Registry Mumber 108141-74-8 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,8,1,4 and 1 respectively; the second part has 2 digits, 7 and 4 respectively. Calculate Digit Verification of CAS Registry Number 108141-74: (8*1)+(7*0)+(6*8)+(5*1)+(4*4)+(3*1)+(2*7)+(1*4)=98 98 % 10 = 8 So 108141-74-8 is a valid CAS Registry Number.