The CAS Registry Mumber 104667-73-4 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,4,6,6 and 7 respectively; the second part has 2 digits, 7 and 3 respectively. Calculate Digit Verification of CAS Registry Number 104667-73: (8*1)+(7*0)+(6*4)+(5*6)+(4*6)+(3*7)+(2*7)+(1*3)=124 124 % 10 = 4 So 104667-73-4 is a valid CAS Registry Number.