The CAS Registry Mumber 82912-30-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,2,9,1 and 2 respectively; the second part has 2 digits, 3 and 0 respectively. Calculate Digit Verification of CAS Registry Number 82912-30: (7*8)+(6*2)+(5*9)+(4*1)+(3*2)+(2*3)+(1*0)=129 129 % 10 = 9 So 82912-30-9 is a valid CAS Registry Number.