Short of hiding the function bar, it isn't possible. But once it's locked they can't make any changes to the function (unless they crack the security).

Hello,

While you are in the protect sheet/workbook window, you can untick the option to select locked cells. If they can't select such cell, it does not show any formulas either.

Br,
Anders

Hi Lea

Select the entire sheet.

Right-click any cell.

Select Format Cells - Protection and tick Hidden

Protect the sheet.

All formulas in the protected sheet will not be visible in the formula bar.

Hope this helps.

Sunny