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.

If you don't have an existing file, use the blank worksheet in Excel. Type a zero in the first row of your column and drag your mouse down to the last row of the column to autofill it with zeros.

By placing a zero before the decimal, the number is more readily recognized as less than one. By configuring a custom number format you can tell Excel to remove leading zeros.