The CAS Registry Mumber 34633-30-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 3,4,6,3 and 3 respectively; the second part has 2 digits, 3 and 0 respectively. Calculate Digit Verification of CAS Registry Number 34633-30: (7*3)+(6*4)+(5*6)+(4*3)+(3*3)+(2*3)+(1*0)=102 102 % 10 = 2 So 34633-30-2 is a valid CAS Registry Number.