The CAS Registry Mumber 83196-16-1 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,3,1,9 and 6 respectively; the second part has 2 digits, 1 and 6 respectively. Calculate Digit Verification of CAS Registry Number 83196-16: (7*8)+(6*3)+(5*1)+(4*9)+(3*6)+(2*1)+(1*6)=141 141 % 10 = 1 So 83196-16-1 is a valid CAS Registry Number.