Create a summary field which is Total of numberField.
Then if table view, place this summary field in a Trailing Grand Summary. It will only display the total in one spot at the left bottom edge of the layout. Table views are pretty poor. Best to use List layout where you can place summary fields in any part in any position and they total properly (depending upon the sorts).
I have found that I can easily make the total appear at the bottom of the column (just where I want it) if I click TOTALS in the TRAILING SUBTOTALS dropdown.
I had hoped to easily add a thousands separator if I go to LAYOUT, access the INSPECTOR, choose CURRENCY or DECIMAL under DATA FORMATTING, and then check the THOUSANDS SEPARATOR box.
Despite going through this procedure, unfortunately none of the figures in the number fields display the separator.
Where have I deviated from the proper procedure to display a thousands separator?