The CAS Registry Mumber 4497-93-2 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 4,4,9 and 7 respectively; the second part has 2 digits, 9 and 3 respectively. Calculate Digit Verification of CAS Registry Number 4497-93: (6*4)+(5*4)+(4*9)+(3*7)+(2*9)+(1*3)=122 122 % 10 = 2 So 4497-93-2 is a valid CAS Registry Number.