The CAS Registry Mumber 5493-96-9 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 5,4,9 and 3 respectively; the second part has 2 digits, 9 and 6 respectively. Calculate Digit Verification of CAS Registry Number 5493-96: (6*5)+(5*4)+(4*9)+(3*3)+(2*9)+(1*6)=119 119 % 10 = 9 So 5493-96-9 is a valid CAS Registry Number.