The CAS Registry Mumber 13497-43-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 1,3,4,9 and 7 respectively; the second part has 2 digits, 4 and 3 respectively. Calculate Digit Verification of CAS Registry Number 13497-43: (7*1)+(6*3)+(5*4)+(4*9)+(3*7)+(2*4)+(1*3)=113 113 % 10 = 3 So 13497-43-3 is a valid CAS Registry Number.