The CAS Registry Mumber 90403-30-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,0,4,0 and 3 respectively; the second part has 2 digits, 3 and 0 respectively. Calculate Digit Verification of CAS Registry Number 90403-30: (7*9)+(6*0)+(5*4)+(4*0)+(3*3)+(2*3)+(1*0)=98 98 % 10 = 8 So 90403-30-8 is a valid CAS Registry Number.