The CAS Registry Mumber 103084-89-5 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,3,0,8 and 4 respectively; the second part has 2 digits, 8 and 9 respectively. Calculate Digit Verification of CAS Registry Number 103084-89: (8*1)+(7*0)+(6*3)+(5*0)+(4*8)+(3*4)+(2*8)+(1*9)=95 95 % 10 = 5 So 103084-89-5 is a valid CAS Registry Number.