The CAS Registry Mumber 5728-48-3 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 5,7,2 and 8 respectively; the second part has 2 digits, 4 and 8 respectively. Calculate Digit Verification of CAS Registry Number 5728-48: (6*5)+(5*7)+(4*2)+(3*8)+(2*4)+(1*8)=113 113 % 10 = 3 So 5728-48-3 is a valid CAS Registry Number.