When you are working on a spreadsheet using Excel sometimes you want to hide columns so they do not appear on the screen or on a printout.
To hide a column right click in the top of the column where it gives the letter of the column like C. Then choose Hide and the column no longer shows but you know it is hidden as that letter is gone, so if I hid C column now it shows columns as A, B, D, E. You can also choose the column and go to the Format menu and choose Column and Hide.
If you have hidden columns usually you just do the reverse by choosing both the column before and after (in my example clicking B and CTRL and clicking D) and right click and choose Unhide. You can also choose the columns and go to Format menu and choose Column and Unhide.
However if you hide column A you must choose the square in the corner by the column letters and above the row numbers. This will select the entire spreadsheet. Then go to the Format menu and choose Column and Unhide and column A reappears.
Hiding columns in Excel can make it much easier to get views and printouts to work like you want them to.
This same information will work for hiding Rows just substitute Rows for Columns and numbers for Row name instead of letters for column names.
Thanks Martha for the question.