The CAS Registry Mumber 4003-22-9 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 4,0,0 and 3 respectively; the second part has 2 digits, 2 and 2 respectively. Calculate Digit Verification of CAS Registry Number 4003-22: (6*4)+(5*0)+(4*0)+(3*3)+(2*2)+(1*2)=39 39 % 10 = 9 So 4003-22-9 is a valid CAS Registry Number.