The CAS Registry Mumber 80982-75-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,0,9,8 and 2 respectively; the second part has 2 digits, 7 and 5 respectively. Calculate Digit Verification of CAS Registry Number 80982-75: (7*8)+(6*0)+(5*9)+(4*8)+(3*2)+(2*7)+(1*5)=158 158 % 10 = 8 So 80982-75-8 is a valid CAS Registry Number.