The CAS Registry Mumber 9003-93-4 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 9,0,0 and 3 respectively; the second part has 2 digits, 9 and 3 respectively. Calculate Digit Verification of CAS Registry Number 9003-93: (6*9)+(5*0)+(4*0)+(3*3)+(2*9)+(1*3)=84 84 % 10 = 4 So 9003-93-4 is a valid CAS Registry Number.