The CAS Registry Mumber 1202-30-8 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 1,2,0 and 2 respectively; the second part has 2 digits, 3 and 0 respectively. Calculate Digit Verification of CAS Registry Number 1202-30: (6*1)+(5*2)+(4*0)+(3*2)+(2*3)+(1*0)=28 28 % 10 = 8 So 1202-30-8 is a valid CAS Registry Number.