The CAS Registry Mumber 808766-62-3 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 8,0,8,7,6 and 6 respectively; the second part has 2 digits, 6 and 2 respectively. Calculate Digit Verification of CAS Registry Number 808766-62: (8*8)+(7*0)+(6*8)+(5*7)+(4*6)+(3*6)+(2*6)+(1*2)=203 203 % 10 = 3 So 808766-62-3 is a valid CAS Registry Number.