The CAS Registry Mumber 453566-94-4 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 4,5,3,5,6 and 6 respectively; the second part has 2 digits, 9 and 4 respectively. Calculate Digit Verification of CAS Registry Number 453566-94: (8*4)+(7*5)+(6*3)+(5*5)+(4*6)+(3*6)+(2*9)+(1*4)=174 174 % 10 = 4 So 453566-94-4 is a valid CAS Registry Number.