The CAS Registry Mumber 4910-03-6 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 4,9,1 and 0 respectively; the second part has 2 digits, 0 and 3 respectively. Calculate Digit Verification of CAS Registry Number 4910-03: (6*4)+(5*9)+(4*1)+(3*0)+(2*0)+(1*3)=76 76 % 10 = 6 So 4910-03-6 is a valid CAS Registry Number.