The CAS Registry Mumber 80672-98-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,0,6,7 and 2 respectively; the second part has 2 digits, 9 and 8 respectively. Calculate Digit Verification of CAS Registry Number 80672-98: (7*8)+(6*0)+(5*6)+(4*7)+(3*2)+(2*9)+(1*8)=146 146 % 10 = 6 So 80672-98-6 is a valid CAS Registry Number.