We use Microsoft Office (2000 version), you can get it on E-Bay for a few quid. Excel is the spreadsheet program in Office
No bells or whistles, but does the job.
Up to the user to fill in the field to do the mathematical stuff. So you have full control.
It's as safe as the drive you have it running on, so always backup to an independent drive (USB pendrive etc).
My advice for what its worth, would be to do unimportant things first and make a few mistakes, then move onto the important things.
With all new bits of technology it takes me hours to do the simplest things. So if you are like me, you'll need to be patient at the beginning