I know the answer, however, how do I know when to use (PV of $1, FV of $1, PVA of $1, and FVA of $1) in each of these situations and on other problems.

The present value of $2,000 to be received nine years from today at 8% interest compounded annually is $1,000.40. (PV of $1, FV of $1, PVA of $1, and FVA of $1) (Use appropriate factor(s) from the tables provided.) The present value factor for determining the present value of $6,300 to be received three years from today at 10% interest compounded semiannually is 0.7462. (PV of $1, FV of $1, PVA of $1, and FVA of $1) (Use appropriate factor(s) from the tables provided.) The present value of $2,000 to be received nine years from today at 8% interest compounded annually is $1,000.40. (PV of $1, FV of $1, PVA of $1, and FVA of $1) (Use appropriate factor(s) from the tables provided.)