It applies absolute, rather than relative addressing (see Excel help, and
other answers here).

As a matter of interest, what is the minus sign after Sum in your formula
trying to do? In my Excel 2003 I get a #NAME? error from your formula. If
the minus sign is a typographical error, I would recommend that you don't
try to retype formulae between the newsgroup and your spreadsheet; instead
use copy and paste to and from your spreadsheet's formula bar.
--
David Biddulph

"applesarah" wrote in message
...
What does the $ in front of a letter or number mean ?