The CAS Registry Mumber 99267-87-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,9,2,6 and 7 respectively; the second part has 2 digits, 8 and 7 respectively. Calculate Digit Verification of CAS Registry Number 99267-87: (7*9)+(6*9)+(5*2)+(4*6)+(3*7)+(2*8)+(1*7)=195 195 % 10 = 5 So 99267-87-5 is a valid CAS Registry Number.