The CAS Registry Mumber 123122-30-5 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,2,3,1,2 and 2 respectively; the second part has 2 digits, 3 and 0 respectively. Calculate Digit Verification of CAS Registry Number 123122-30: (8*1)+(7*2)+(6*3)+(5*1)+(4*2)+(3*2)+(2*3)+(1*0)=65 65 % 10 = 5 So 123122-30-5 is a valid CAS Registry Number.