The CAS Registry Mumber 18444-94-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 1,8,4,4 and 4 respectively; the second part has 2 digits, 9 and 4 respectively. Calculate Digit Verification of CAS Registry Number 18444-94: (7*1)+(6*8)+(5*4)+(4*4)+(3*4)+(2*9)+(1*4)=125 125 % 10 = 5 So 18444-94-5 is a valid CAS Registry Number.