Hi Lea,

I don't know of any shortcut for this. There is a list of column and row shortcuts here. You'll see there are ways to group and ungroup rows and columns which might be of use.

Mynda

Select one column, hold Ctrl and press 0 on the keyboard.

If your office version is 2007 or above, you can try: hold Alt until some characters appear on the ribbon, and then press H,O,U,C, you will hide the column selected.

However, i think right click the column and select hide column is a more easier way.

Ctrl+0 hides, but I thought the question is what shortcut unhides columns.

I don't know of any shortcuts to unhide columns, but like Clark suggests, you can use the Alt menu > H O U L (select cells that span hidden columns first).

Although, I agree with Clark, the mouse is easier if it's an option.

Mynda Treacy said
Ctrl+0 hides, but I thought the question is what shortcut unhides columns.

I don't know of any shortcuts to unhide columns, but like Clark suggests, you can use the Alt menu > H O U L (select cells that span hidden columns first).

Although, I agree with Clark, the mouse is easier if it's an option.  

I might misunderstood the question. Unhide all column, there may be a way. First Ctrl+A select all the worksheet, then try ctrl+shift+) or ctrl+shift+0. I don't have computer around my hand, so i don't know whether it works.