The CAS Registry Mumber 49711-99-1 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 4,9,7,1 and 1 respectively; the second part has 2 digits, 9 and 9 respectively. Calculate Digit Verification of CAS Registry Number 49711-99: (7*4)+(6*9)+(5*7)+(4*1)+(3*1)+(2*9)+(1*9)=151 151 % 10 = 1 So 49711-99-1 is a valid CAS Registry Number.