When you type a seven-or-ten-digit phone number into an Excel cell that uses the phone number format, Excel will automatically change the way the number looks so that it appears as a phone number ...

Combine an Excel custom format with data validation and remove the pressure for input perfection from personnel by letting Excel do the work.

You can add a zero before a number in Google Sheets and Excel using this tutorial. You need to change cell formatting or use function.

You can subtract numbers in Microsoft Excel in a few different ways, depending on your data and formatting.