The CAS Registry Mumber 348-97-0 includes 6 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 3 digits, 3,4 and 8 respectively; the second part has 2 digits, 9 and 7 respectively. Calculate Digit Verification of CAS Registry Number 348-97: (5*3)+(4*4)+(3*8)+(2*9)+(1*7)=80 80 % 10 = 0 So 348-97-0 is a valid CAS Registry Number.