The CAS Registry Mumber 99474-52-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,9,4,7 and 4 respectively; the second part has 2 digits, 5 and 2 respectively. Calculate Digit Verification of CAS Registry Number 99474-52: (7*9)+(6*9)+(5*4)+(4*7)+(3*4)+(2*5)+(1*2)=189 189 % 10 = 9 So 99474-52-9 is a valid CAS Registry Number.