Final answer:
To hide column J in a worksheet, click the column header, right-click, and select 'Hide'. The column will be hidden, but can be unhidden later by selecting adjacent columns and choosing 'Unhide'.
Step-by-step explanation:
To hide column J in a Mileage Log worksheet, you should first select the column by clicking on the header labeled 'J'. Then, right-click to open the contextual menu and choose the 'Hide' option. The entire column J will become invisible on your worksheet. You can unhide it later by selecting the columns on either side of the hidden column, right-clicking, and then choosing 'Unhide' from the menu.