The CAS Registry Mumber 99474-50-7 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 0 respectively. Calculate Digit Verification of CAS Registry Number 99474-50: (7*9)+(6*9)+(5*4)+(4*7)+(3*4)+(2*5)+(1*0)=187 187 % 10 = 7 So 99474-50-7 is a valid CAS Registry Number.