The CAS Registry Mumber 127347-11-9 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,2,7,3,4 and 7 respectively; the second part has 2 digits, 1 and 1 respectively. Calculate Digit Verification of CAS Registry Number 127347-11: (8*1)+(7*2)+(6*7)+(5*3)+(4*4)+(3*7)+(2*1)+(1*1)=119 119 % 10 = 9 So 127347-11-9 is a valid CAS Registry Number.