The CAS Registry Mumber 20898-06-0 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 2,0,8,9 and 8 respectively; the second part has 2 digits, 0 and 6 respectively. Calculate Digit Verification of CAS Registry Number 20898-06: (7*2)+(6*0)+(5*8)+(4*9)+(3*8)+(2*0)+(1*6)=120 120 % 10 = 0 So 20898-06-0 is a valid CAS Registry Number.