The CAS Registry Mumber 3081-32-1 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 3,0,8 and 1 respectively; the second part has 2 digits, 3 and 2 respectively. Calculate Digit Verification of CAS Registry Number 3081-32: (6*3)+(5*0)+(4*8)+(3*1)+(2*3)+(1*2)=61 61 % 10 = 1 So 3081-32-1 is a valid CAS Registry Number.