The CAS Registry Mumber 4599-40-0 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 4,5,9 and 9 respectively; the second part has 2 digits, 4 and 0 respectively. Calculate Digit Verification of CAS Registry Number 4599-40: (6*4)+(5*5)+(4*9)+(3*9)+(2*4)+(1*0)=120 120 % 10 = 0 So 4599-40-0 is a valid CAS Registry Number.