Present Value of an Annuity

Find the present value of the following ordinary annuities if discounting occurs once a year.

1) $300 per year for 10 years at 10 percent

answer $4,781.23

2) $150 per year for 5 years at 5 percent

answer $828.84

3) $250 per year for 5 years at 0 percent

answer $350

Is this correct?