The CAS Registry Mumber 149285-99-4 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,4,9,2,8 and 5 respectively; the second part has 2 digits, 9 and 9 respectively. Calculate Digit Verification of CAS Registry Number 149285-99: (8*1)+(7*4)+(6*9)+(5*2)+(4*8)+(3*5)+(2*9)+(1*9)=174 174 % 10 = 4 So 149285-99-4 is a valid CAS Registry Number.