The CAS Registry Mumber 97814-03-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,7,8,1 and 4 respectively; the second part has 2 digits, 0 and 3 respectively. Calculate Digit Verification of CAS Registry Number 97814-03: (7*9)+(6*7)+(5*8)+(4*1)+(3*4)+(2*0)+(1*3)=164 164 % 10 = 4 So 97814-03-4 is a valid CAS Registry Number.