i keep getting these wrong

Answer questions 1-8 for a $250,000 home purchase using a conventional fixed rate mortgage from a private lender. Reminder: mortgage payments are monthly so use monthly compounding for all mortgage calculations. Round Annuity Factors to 4 decimal places; round dollar amounts to the penny. 1. What is the dollar amount of the down payment if the down payment is 10%? 2. What is the minimum dollar amount of the down payment that will result in the borrower not having to pay for Private Mortgage Insurance? 3. What is the annuity factor for a 30-year mortgage if the mortgage rate is 3.96%? 4. What is the loan (mortgage) amount if the down payment is 10%? 5. What is the monthly mortgage payment for a 30-year fixed rate mortgage if the mortgage rate is 3.96% for a loan with a 10% down payment? 6. What is the annuity factor for a 15-year mortgage if the mortgage rate is 3.36%? 7. What is the monthly mortgage payment for a 15-year fixed rate mortgage if the mortgage rate is 3.36% for a loan with a 10% down payment? 8. Use the monthly mortgage payments from #4 and #6 to calculate the total interest paid on each loan. What is the difference in total interest paid between the 30-year mortgage and the 15-year mortgage? 9. Which loan is better, the 30-year or the 15-year? 10. What is the amount of annual income necessary to qualify for a $2,100 monthly PITI payment assuming the lender follows traditional lending rules