The CAS Registry Mumber 4603-89-8 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 4,6,0 and 3 respectively; the second part has 2 digits, 8 and 9 respectively. Calculate Digit Verification of CAS Registry Number 4603-89: (6*4)+(5*6)+(4*0)+(3*3)+(2*8)+(1*9)=88 88 % 10 = 8 So 4603-89-8 is a valid CAS Registry Number.