The CAS Registry Mumber 104703-16-4 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,4,7,0 and 3 respectively; the second part has 2 digits, 1 and 6 respectively. Calculate Digit Verification of CAS Registry Number 104703-16: (8*1)+(7*0)+(6*4)+(5*7)+(4*0)+(3*3)+(2*1)+(1*6)=84 84 % 10 = 4 So 104703-16-4 is a valid CAS Registry Number.