The CAS Registry Mumber 17364-97-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 1,7,3,6 and 4 respectively; the second part has 2 digits, 9 and 7 respectively. Calculate Digit Verification of CAS Registry Number 17364-97: (7*1)+(6*7)+(5*3)+(4*6)+(3*4)+(2*9)+(1*7)=125 125 % 10 = 5 So 17364-97-5 is a valid CAS Registry Number.