The CAS Registry Mumber 92397-66-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,2,3,9 and 7 respectively; the second part has 2 digits, 6 and 6 respectively. Calculate Digit Verification of CAS Registry Number 92397-66: (7*9)+(6*2)+(5*3)+(4*9)+(3*7)+(2*6)+(1*6)=165 165 % 10 = 5 So 92397-66-5 is a valid CAS Registry Number.