The CAS Registry Mumber 199169-30-7 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,9,9,1,6 and 9 respectively; the second part has 2 digits, 3 and 0 respectively. Calculate Digit Verification of CAS Registry Number 199169-30: (8*1)+(7*9)+(6*9)+(5*1)+(4*6)+(3*9)+(2*3)+(1*0)=187 187 % 10 = 7 So 199169-30-7 is a valid CAS Registry Number.