You have located a warehouse property to purchase at a price of $$320,000.$ You plan to make a $20\%$ downpayment of $$64,000.$ Interest rates are rising quickly, but you$$ve managed to secure a fixed$-$rate commercial mortgage at $4\mathrm{.}5\%.$ Commercial mortgages are typically much shorter than consumer mortgages like home loans, so the lender has offered you a $10-$year term.

Set up a mortgage spreadsheet model $($including an amortization table

$1)$ What is the total interest paid on this mortgage over the $10$ year term?

$2)$What is the ending balance on the mortgage after the first year?

$3)$Sometimes commercial lenders will amortize a loan for $10$ years, but require the borrower to pay off the loan in a shorter period of time by paying off the rest of the loan in one final payment, known as a "balloon" payment. How much would you have to pay for that balloon payment $($the ending balance$)$ if your loan was still amortized for $10$ years but you had to pay it off in $5$ years?

$4)$How much would your monthly payment be if you managed to negotiate the price of the warehouse property down to $$275,000$ from $$320,000,$ but kept your downpayment the same?