Newer versions: Excel 2007, 2010, 2013, 2016
Archived older versions: Excel 97 through 2003
For working with piles of numbers you usually need a spreadsheet program. Such a program is designed to make it easy to crunch a bunch of numbers into usable results by calculating total and averages, or using a complex formula to analyze the numbers.
Excel 2007, 2010, 2013, and 2016 use a different style of interface than older versions of Excel. They put controls for the most common actions on ribbon tabs instead of toolbars.
Choose the lessons that match the version of Excel that you have and get started!
If you think you know what you are doing with Excel already but need a refresher, you might enjoy Microsoft Excel Boot Camp by GraduateTutor.com. It's a free webinar. [I have no association with this company.]