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 use SUMIF in Google Sheets to add numbers together that are associated with a date range, specific text, or meet a numeric criterion.

Learn how to round numbers in Google Sheets using the ROUND, ROUNDUP, ROUNDDOWN, MROUND, INT, FLOO, CEILING functions.

You may need to add cells in Google Sheets if your spreadsheet needs to contain more information than it currently has room for.