The CAS Registry Mumber 8049-85-2 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 8,0,4 and 9 respectively; the second part has 2 digits, 8 and 5 respectively. Calculate Digit Verification of CAS Registry Number 8049-85: (6*8)+(5*0)+(4*4)+(3*9)+(2*8)+(1*5)=112 112 % 10 = 2 So 8049-85-2 is a valid CAS Registry Number.