Apple has added spreadsheet software to its iWork suite of office applications.

The new Numbers application joins the presentation and page-layout programs that already make up the package.

Keynote, Pages, and the newly added Numbers will make up iWork '08. The $79 suite, which is now shipping, was unveiled yesterday at Apple's headquarters.

Apple CEO Steve Jobs described Numbers as a spreadsheet application "done in the style of Keynote and Pages." Among its features are "intelligent tables," that allow users to sort and filter by clicking on headers, as well as chart creation, image management, text labels, and the ability to add photos and diagrams. A flexible canvas feature lets users put multiple sheets on a canvas and tie them together in formulas but not in formatting.

According to Jobs, Numbers supports the ability to import and export "almost all" documents from Microsoft Excel.

The changes to Keynote are lead by Instant Alpha - a feature that lets users take the background out of images without using masking tools from image-editing software - and Smart Builds - which makes it easy to generate animations in presentation slides.

Other Keynote enhancements include new text effects and transitions.

Pages now features a word-processing mode in addition to a page-layout one. There's also a contextual format bar and a change-tracking for looking at revisions. The application features 140 included templates.

Like the newly released iLife '08, the latest version of iWork will run on Mac OS X 10.4 as well as the upcoming OS X 10.5 upgrade.