The CAS Registry Mumber 4727-78-0 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 4,7,2 and 7 respectively; the second part has 2 digits, 7 and 8 respectively. Calculate Digit Verification of CAS Registry Number 4727-78: (6*4)+(5*7)+(4*2)+(3*7)+(2*7)+(1*8)=110 110 % 10 = 0 So 4727-78-0 is a valid CAS Registry Number.