Excel removes parenthesis when editing formula

Hi,

When I edit the formula below Excel removes the parenthesis {} & then the formula doesn't work.

{=SUM(SUMIFS(Tables!$G$3:$G$7,Tables!$F$3:$F$7,Data!K7:Z7))}

If I add them in manually then it just changes the formatting to text. FYI-the formula totals up an assigned number (in a table) for each text value (in a table) within a data range.