The CAS Registry Mumber 21314-96-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 2,1,3,1 and 4 respectively; the second part has 2 digits, 9 and 6 respectively. Calculate Digit Verification of CAS Registry Number 21314-96: (7*2)+(6*1)+(5*3)+(4*1)+(3*4)+(2*9)+(1*6)=75 75 % 10 = 5 So 21314-96-5 is a valid CAS Registry Number.