The CAS Registry Mumber 14384-71-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 1,4,3,8 and 4 respectively; the second part has 2 digits, 7 and 1 respectively. Calculate Digit Verification of CAS Registry Number 14384-71: (7*1)+(6*4)+(5*3)+(4*8)+(3*4)+(2*7)+(1*1)=105 105 % 10 = 5 So 14384-71-5 is a valid CAS Registry Number.