The CAS Registry Mumber 96223-53-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,6,2,2 and 3 respectively; the second part has 2 digits, 5 and 3 respectively. Calculate Digit Verification of CAS Registry Number 96223-53: (7*9)+(6*6)+(5*2)+(4*2)+(3*3)+(2*5)+(1*3)=139 139 % 10 = 9 So 96223-53-9 is a valid CAS Registry Number.