The CAS Registry Mumber 96791-93-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,6,7,9 and 1 respectively; the second part has 2 digits, 9 and 3 respectively. Calculate Digit Verification of CAS Registry Number 96791-93: (7*9)+(6*6)+(5*7)+(4*9)+(3*1)+(2*9)+(1*3)=194 194 % 10 = 4 So 96791-93-4 is a valid CAS Registry Number.