The CAS Registry Mumber 7193-16-0 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 7,1,9 and 3 respectively; the second part has 2 digits, 1 and 6 respectively. Calculate Digit Verification of CAS Registry Number 7193-16: (6*7)+(5*1)+(4*9)+(3*3)+(2*1)+(1*6)=100 100 % 10 = 0 So 7193-16-0 is a valid CAS Registry Number.