The CAS Registry Mumber 193602-04-9 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,9,3,6,0 and 2 respectively; the second part has 2 digits, 0 and 4 respectively. Calculate Digit Verification of CAS Registry Number 193602-04: (8*1)+(7*9)+(6*3)+(5*6)+(4*0)+(3*2)+(2*0)+(1*4)=129 129 % 10 = 9 So 193602-04-9 is a valid CAS Registry Number.