The CAS Registry Mumber 16256-96-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 1,6,2,5 and 6 respectively; the second part has 2 digits, 9 and 6 respectively. Calculate Digit Verification of CAS Registry Number 16256-96: (7*1)+(6*6)+(5*2)+(4*5)+(3*6)+(2*9)+(1*6)=115 115 % 10 = 5 So 16256-96-5 is a valid CAS Registry Number.