The CAS Registry Mumber 4752-55-0 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 4,7,5 and 2 respectively; the second part has 2 digits, 5 and 5 respectively. Calculate Digit Verification of CAS Registry Number 4752-55: (6*4)+(5*7)+(4*5)+(3*2)+(2*5)+(1*5)=100 100 % 10 = 0 So 4752-55-0 is a valid CAS Registry Number.