How to change number format in Google Docs spreadsheet?
Number format option is used to keep the appropriate number format suitable for the worksheet file. You have two options to change or keep new number format.
Option 1: Click 123 option in the tool bar and select the desired option.
Option 2: Click Format → Number → Select the required format.
To keep the Custom number format, click Format → Number → More Formats → Custom number format
In the Custom number formats dialog box, select the required option and click Apply.