The CAS Registry Mumber 4831-03-2 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 4,8,3 and 1 respectively; the second part has 2 digits, 0 and 3 respectively. Calculate Digit Verification of CAS Registry Number 4831-03: (6*4)+(5*8)+(4*3)+(3*1)+(2*0)+(1*3)=82 82 % 10 = 2 So 4831-03-2 is a valid CAS Registry Number.