The CAS Registry Mumber 4610-99-5 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 4,6,1 and 0 respectively; the second part has 2 digits, 9 and 9 respectively. Calculate Digit Verification of CAS Registry Number 4610-99: (6*4)+(5*6)+(4*1)+(3*0)+(2*9)+(1*9)=85 85 % 10 = 5 So 4610-99-5 is a valid CAS Registry Number.