The CAS Registry Mumber 108321-62-6 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,8,3,2 and 1 respectively; the second part has 2 digits, 6 and 2 respectively. Calculate Digit Verification of CAS Registry Number 108321-62: (8*1)+(7*0)+(6*8)+(5*3)+(4*2)+(3*1)+(2*6)+(1*2)=96 96 % 10 = 6 So 108321-62-6 is a valid CAS Registry Number.