The CAS Registry Mumber 82112-32-1 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 2 respectively. Calculate Digit Verification of CAS Registry Number 82112-32: (7*8)+(6*2)+(5*1)+(4*1)+(3*2)+(2*3)+(1*2)=91 91 % 10 = 1 So 82112-32-1 is a valid CAS Registry Number.