The CAS Registry Mumber 4940-44-7 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 4,9,4 and 0 respectively; the second part has 2 digits, 4 and 4 respectively. Calculate Digit Verification of CAS Registry Number 4940-44: (6*4)+(5*9)+(4*4)+(3*0)+(2*4)+(1*4)=97 97 % 10 = 7 So 4940-44-7 is a valid CAS Registry Number.