The CAS Registry Mumber 4898-56-0 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 4,8,9 and 8 respectively; the second part has 2 digits, 5 and 6 respectively. Calculate Digit Verification of CAS Registry Number 4898-56: (6*4)+(5*8)+(4*9)+(3*8)+(2*5)+(1*6)=140 140 % 10 = 0 So 4898-56-0 is a valid CAS Registry Number.