How would you calculate the volume of buffer to add to a tab

How would you calculate the volume of buffer to add to a tablet that is 9000 FCC units, to make a solution at 1000 units/mL concentration?

As a tablet contains 9000 FCC and final concentration required is 1000 FCC/mL.

We have to make the final volume of the solution to 9 ml (volume coming from tablet will be part of toatal 9 mL, remaing amount will be buffer q. s.)