The CAS Registry Mumber 140406-71-9 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,4,0,4,0 and 6 respectively; the second part has 2 digits, 7 and 1 respectively. Calculate Digit Verification of CAS Registry Number 140406-71: (8*1)+(7*4)+(6*0)+(5*4)+(4*0)+(3*6)+(2*7)+(1*1)=89 89 % 10 = 9 So 140406-71-9 is a valid CAS Registry Number.