The CAS Registry Mumber 1157-69-3 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 1,1,5 and 7 respectively; the second part has 2 digits, 6 and 9 respectively. Calculate Digit Verification of CAS Registry Number 1157-69: (6*1)+(5*1)+(4*5)+(3*7)+(2*6)+(1*9)=73 73 % 10 = 3 So 1157-69-3 is a valid CAS Registry Number.