The CAS Registry Mumber 104667-64-3 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, 6 and 4 respectively. Calculate Digit Verification of CAS Registry Number 104667-64: (8*1)+(7*0)+(6*4)+(5*6)+(4*6)+(3*7)+(2*6)+(1*4)=123 123 % 10 = 3 So 104667-64-3 is a valid CAS Registry Number.