The CAS Registry Mumber 4479-33-8 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 4,4,7 and 9 respectively; the second part has 2 digits, 3 and 3 respectively. Calculate Digit Verification of CAS Registry Number 4479-33: (6*4)+(5*4)+(4*7)+(3*9)+(2*3)+(1*3)=108 108 % 10 = 8 So 4479-33-8 is a valid CAS Registry Number.