The CAS Registry Mumber 73444-27-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,3,4,4 and 4 respectively; the second part has 2 digits, 2 and 7 respectively. Calculate Digit Verification of CAS Registry Number 73444-27: (7*7)+(6*3)+(5*4)+(4*4)+(3*4)+(2*2)+(1*7)=126 126 % 10 = 6 So 73444-27-6 is a valid CAS Registry Number.