Apple iWork '08 - Manual (Page 67)

Chapter 2 Getting Started with Numbers 67
To resize your table by dragging selection handles:
m Select your new table and then experiment with the various selection handles to
discover how they affect table size.
Before continuing, delete the table you’ve been resizing and add a fresh one.
To add a fresh table:
1 Select the table you’ve been using, and press Delete.
2 Add a Plain table, and apply the Basic table style to it.
Drag this handle or the opposite
handle up or down to expand or
contract rows.
Drag this handle or the opposite
handle to the right or left to expand
or contract columns.
Drag any of the four corner handles
diagonally to resize columns and
rows at the same time.