The CAS Registry Mumber 4366-93-2 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 4,3,6 and 6 respectively; the second part has 2 digits, 9 and 3 respectively. Calculate Digit Verification of CAS Registry Number 4366-93: (6*4)+(5*3)+(4*6)+(3*6)+(2*9)+(1*3)=102 102 % 10 = 2 So 4366-93-2 is a valid CAS Registry Number.