A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
Click on the column header of the column to the left of the hidden columns, then Shift+Click on the column header of the column to the right of the hidden columns.
On the Home tab of the ribbon, in the Cells group, select Format > Hide & Unhide > Unhide Columns.
If that doesn't work, select Format > Column Width..., enter a positive number (for example 10) and click OK.