The CAS Registry Mumber 132216-09-2 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,3,2,2,1 and 6 respectively; the second part has 2 digits, 0 and 9 respectively. Calculate Digit Verification of CAS Registry Number 132216-09: (8*1)+(7*3)+(6*2)+(5*2)+(4*1)+(3*6)+(2*0)+(1*9)=82 82 % 10 = 2 So 132216-09-2 is a valid CAS Registry Number.