The CAS Registry Mumber 630393-89-4 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 6,3,0,3,9 and 3 respectively; the second part has 2 digits, 8 and 9 respectively. Calculate Digit Verification of CAS Registry Number 630393-89: (8*6)+(7*3)+(6*0)+(5*3)+(4*9)+(3*3)+(2*8)+(1*9)=154 154 % 10 = 4 So 630393-89-4 is a valid CAS Registry Number.