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.

Percentages aren't always easy to calculate, but one of the best tools in Excel's toolbox is calculating percentages for you. Here's how to do it.

Excel has a surprising limitation that you may not discover until you try to enter more than 15 digits in a cell. The application can only store numbers with15 digits of precision.