Average Sales per Day Formula Over Selected From To Dates

Average Sales per Day Formula Over Selected From To Dates

Hi

I have a Sales table wherein I have Invoice Dates, Item Description, Qty per Invoice, Invoice value.

I have made a pivot for sales data with different user filters. One of them is Sale Invoice From Date and To Date.

I want a formula to calculate average sale qty per day with respect to the number of days selected in the date filter including the selected dates.