The CAS Registry Mumber 13444-93-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 1,3,4,4 and 4 respectively; the second part has 2 digits, 9 and 3 respectively. Calculate Digit Verification of CAS Registry Number 13444-93: (7*1)+(6*3)+(5*4)+(4*4)+(3*4)+(2*9)+(1*3)=94 94 % 10 = 4 So 13444-93-4 is a valid CAS Registry Number.