The CAS Registry Mumber 67347-98-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 6,7,3,4 and 7 respectively; the second part has 2 digits, 9 and 8 respectively. Calculate Digit Verification of CAS Registry Number 67347-98: (7*6)+(6*7)+(5*3)+(4*4)+(3*7)+(2*9)+(1*8)=162 162 % 10 = 2 So 67347-98-2 is a valid CAS Registry Number.