Make row 1 a Header Row, then use SUM(A).
SUM, and several other similar functions omit header and footer rows from 'full column' references, allowing the formula to be placed in a Header row or a Footer row of the coulumn they are summing.
To convert the row, select any cell in the table to activateed the Table and show the row and column reference tabs.
Hover the pointer in the space between the row 1 tab and the table, then click on the v that appears to open the short menu shown below.

If the menu shows the items listed above, do nothing. Row 1, where the v showing was clicked, is already a Header row.
If the menu shows the items listed below, choose the Convert to Header Row to convert the selected row to a Header row.

Here's the full table, with a Row 1 as a header row, and row 11 converted to a Footer row. Column D is being summed by the formula displayed below the table, placed in D11.
Note that the highlighting of the range does not include either cell D1 (in a Header row) or D11 (in a Footer row.

Regards,
Barry