The CAS Registry Mumber 11129-69-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 1,1,1,2 and 9 respectively; the second part has 2 digits, 6 and 9 respectively. Calculate Digit Verification of CAS Registry Number 11129-69: (7*1)+(6*1)+(5*1)+(4*2)+(3*9)+(2*6)+(1*9)=74 74 % 10 = 4 So 11129-69-4 is a valid CAS Registry Number.