The CAS Registry Mumber 98791-14-1 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,8,7,9 and 1 respectively; the second part has 2 digits, 1 and 4 respectively. Calculate Digit Verification of CAS Registry Number 98791-14: (7*9)+(6*8)+(5*7)+(4*9)+(3*1)+(2*1)+(1*4)=191 191 % 10 = 1 So 98791-14-1 is a valid CAS Registry Number.