Value of Future Payments

Finding present value of an investment…?
For the following investment plan, how much must be invested today at 6.25% pa, compounded monthly, if the first payment is made a month from today? The investment plan is: 10 monthly payments of $900.

Textbook answer says $8747.47, but I need to know the steps, thanks.
Using PVA=R[[1-(1+i)^-n]/i] (R is payment..)

1) at the time of his son birth ,a man invest a certain sum of money 8% compounded quarterly to provide payments of 6000 each for four years. the first payment to be on his son’s 20th birthday.how much does the father invest?
2) on his 45th birthday a man buys an annuity from an insurance co.which credits interest at 0.09 m=4 the annuity will provide 15 yrs of 3000monly payments to himself or his wife ,and its term will begin on his 50th b-day.what single payment does he make on his 45th b-day?