How do I calculate field in the first empty field named DaysOnMarket that will calculate the number of days each sold property was on the market when it sold. Add a caption of Days on Market.

How do I calculate another field in the first empty field named ListComm that will calculate the listing agent's commission based on the sales price and a listing commission rate of 3.5%. Add a caption of Listing Commission and format the field as Currency

How do i calculate another field in the first empty field named SellComm that will calculate the listing agent's commission based on the sales price and a selling commission rate of 2.5%. Add a caption of Selling Commission and format the field as Currency

Please help me calculate the 3 fields in access form