Excelling at hiding and unhiding rows and columns can help you clean up your spreadsheet and focus on the most important data. Here's how you can do it:

Hiding Rows or Columns:

There are three ways to hide rows or columns:

1. Right-click method:
- Select the row(s) or column(s) you want to hide.
- Right-click anywhere on the selection.
- Choose "Hide" from the context menu.

2. Shortcut method:
- Select the row(s) or column(s) you want to hide.
- Use the keyboard shortcut:
- For rows: Press `Ctrl + 9` (Windows) or `Command + 9` (Mac).
- For columns: Press `Ctrl + 0` (Windows) or `Command + 0` (Mac).

3. Ribbon method:
- Select the row(s) or column(s) you want to hide.
- Go to the "Home" tab on the Excel ribbon.
- In the "Cells" group, click the "Format" dropdown arrow.
- Under "Visibility," choose "Hide Rows" or "Hide Columns" depending on your selection.

Unhiding Rows or Columns:

There are two ways to unhide rows or columns:

1. Clicking the double line: Look at the edges between rows or columns. Where a row or column is hidden, you'll see a double line instead of a single line separating the rows/columns. Click on this double line anywhere along its length to unhide the hidden row(s) or column(s).

2. Ribbon method:
- Select the row(s) or column(s) bordering the hidden area (the rows/columns next to where you want to unhide).
- Go to the "Home" tab on the Excel ribbon.
- In the "Cells" group, click the "Format" dropdown arrow.
- Under "Visibility," choose "Unhide Rows" or "Unhide Columns" depending on what you want to unhide.

Tips:

* To unhide all hidden rows or columns, press `Ctrl + Shift + 9` (Windows) or `Command + Shift + 9` (Mac) to unhide all rows and `Ctrl + Shift + 0` (Windows) or `Command + Shift + 0` (Mac) to unhide all columns.
* Be careful when hiding rows or columns, especially if you have formulas that reference hidden cells. Those formulas may not work correctly until the hidden rows/columns are unhidden.