If you have Excel and the file is not protected, then you should be able to work on it. If not, open the e-mail on a computer with Excel or try opening it through something like Google Docs.
how to create a excel sheet
Pfa the excel sheet
Add a sheet
They are the same thing, excel is Microsoft's spreadsheet programme.
Calculating DSCR in Excel sheet
Select the sheet.
A spread sheet
17,179,869,184 cells in one excel
I believe chart sheet.
Cell protection only kicks in when you protect the entire sheet. So for the cell to be protected, then the sheet has to be protected.
You can click and drag a sheet tab to change its position.
Excel is a spread sheet programme, PowerPoint is more of a movie programme.