The CAS Registry Mumber 69339-97-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 6,9,3,3 and 9 respectively; the second part has 2 digits, 9 and 7 respectively. Calculate Digit Verification of CAS Registry Number 69339-97: (7*6)+(6*9)+(5*3)+(4*3)+(3*9)+(2*9)+(1*7)=175 175 % 10 = 5 So 69339-97-5 is a valid CAS Registry Number.