The CAS Registry Mumber 99289-48-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,9,2,8 and 9 respectively; the second part has 2 digits, 4 and 8 respectively. Calculate Digit Verification of CAS Registry Number 99289-48: (7*9)+(6*9)+(5*2)+(4*8)+(3*9)+(2*4)+(1*8)=202 202 % 10 = 2 So 99289-48-2 is a valid CAS Registry Number.