The CAS Registry Mumber 19183-27-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 1,9,1,8 and 3 respectively; the second part has 2 digits, 2 and 7 respectively. Calculate Digit Verification of CAS Registry Number 19183-27: (7*1)+(6*9)+(5*1)+(4*8)+(3*3)+(2*2)+(1*7)=118 118 % 10 = 8 So 19183-27-8 is a valid CAS Registry Number.