The CAS Registry Mumber 11139-69-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 1,1,1,3 and 9 respectively; the second part has 2 digits, 6 and 9 respectively. Calculate Digit Verification of CAS Registry Number 11139-69: (7*1)+(6*1)+(5*1)+(4*3)+(3*9)+(2*6)+(1*9)=78 78 % 10 = 8 So 11139-69-8 is a valid CAS Registry Number.