The CAS Registry Mumber 183489-02-3 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,8,3,4,8 and 9 respectively; the second part has 2 digits, 0 and 2 respectively. Calculate Digit Verification of CAS Registry Number 183489-02: (8*1)+(7*8)+(6*3)+(5*4)+(4*8)+(3*9)+(2*0)+(1*2)=163 163 % 10 = 3 So 183489-02-3 is a valid CAS Registry Number.