The CAS Registry Mumber 82408-66-0 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,2,4,0 and 8 respectively; the second part has 2 digits, 6 and 6 respectively. Calculate Digit Verification of CAS Registry Number 82408-66: (7*8)+(6*2)+(5*4)+(4*0)+(3*8)+(2*6)+(1*6)=130 130 % 10 = 0 So 82408-66-0 is a valid CAS Registry Number.