Gnumeric 1.12.35 Description by the Software Developer:
"Gnumeric is a powerful and easy to use spreadsheet using GNOME. Its goal is to provide a full featured spreadsheet and a smooth migration path for people and organizations currently using proprietary applications. Gnumeric provides more sheet functions and greatly improved accuracy when compared to Microsoft's Excel. A plugin system lets you extend Gnumeric, adding functions, I/O formats, and real time data capabilities.
The existing Python, Guile, and Perl plugins let you define complex functions. Gnumeric is capable of reading and writing MS Excel, and reading Lotus, Applix, Quattro Pro, OpenCalc, XBase, DIF, SYLK, HTML, Psion, MPS, oleo, sc, misc. text formats, and its native XML. It can also generate Latex, HTML, and others."