The CAS Registry Mumber 18199-96-7 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 1,8,1,9 and 9 respectively; the second part has 2 digits, 9 and 6 respectively. Calculate Digit Verification of CAS Registry Number 18199-96: (7*1)+(6*8)+(5*1)+(4*9)+(3*9)+(2*9)+(1*6)=147 147 % 10 = 7 So 18199-96-7 is a valid CAS Registry Number.