$9\mathrm{.}4.$ Find the following values assuming a regular, or ordinary, annuity:

a$.$ The present value of $$400$ per year for ten years at $10$ percent

b$.$ The future value of $$400$ per year for ten years at $10$ percent

c$.$ The present value of $$200$ per year for five years at $5$ percent

d$.$ The future value of $$200$ per year for five years at $5$ percent

$9\mathrm{.}5.$ Repeat problem $9\mathrm{.}4,$ but assume the annuities are annuities due.