The CAS Registry Mumber 96223-55-1 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 5 respectively. Calculate Digit Verification of CAS Registry Number 96223-55: (7*9)+(6*6)+(5*2)+(4*2)+(3*3)+(2*5)+(1*5)=141 141 % 10 = 1 So 96223-55-1 is a valid CAS Registry Number.