Just a few days after Apple filed for the Mactel Trademark it seems they have also filed for the Trademark for the name 'Numbers'. The trademark filing describes it simply as 'Computer Software'.
Although purely speculation the name Numbers conforms perfectly to the naming scheme within the iWorks package, currently containing just two applications by the names of Keynote and Pages, a presentation app and word processor.
It seems that overall Apple are pushing the sale of iWorks by putting 30 day trials into every retail box of Tiger.