The CAS Registry Mumber 139618-33-0 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,3,9,6,1 and 8 respectively; the second part has 2 digits, 3 and 3 respectively. Calculate Digit Verification of CAS Registry Number 139618-33: (8*1)+(7*3)+(6*9)+(5*6)+(4*1)+(3*8)+(2*3)+(1*3)=150 150 % 10 = 0 So 139618-33-0 is a valid CAS Registry Number.