The CAS Registry Mumber 80761-82-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,0,7,6 and 1 respectively; the second part has 2 digits, 8 and 2 respectively. Calculate Digit Verification of CAS Registry Number 80761-82: (7*8)+(6*0)+(5*7)+(4*6)+(3*1)+(2*8)+(1*2)=136 136 % 10 = 6 So 80761-82-6 is a valid CAS Registry Number.