The CAS Registry Mumber 82112-30-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,2,1,1 and 2 respectively; the second part has 2 digits, 3 and 0 respectively. Calculate Digit Verification of CAS Registry Number 82112-30: (7*8)+(6*2)+(5*1)+(4*1)+(3*2)+(2*3)+(1*0)=89 89 % 10 = 9 So 82112-30-9 is a valid CAS Registry Number.