Apache OpenOffice is a free download at www.openoffice.org.
OpenOffice works on Windows, Mac and Linux. The OpenOffice Suite is similar to MS Office.
The OpenOffice Suite Includes
Writer ( Word Processor ) similar to MS Word
Calc ( Spreadsheet ) similar to MS Excel
Impress ( Presentation ) similar to MS PowerPoint
Base ( Database ) similar to MS Access
Draw ( Vector Drawing ) similar to Office Drawing
Math ( Formula Editor ) similar to Ms Equation Editor
This tutorial shows the user interface of Calc 4. The items include, toolbars, menus, SideBar, cells, split, What Is This, and many other items.