Good question!

If you are approaching this from an academic "I want to know everything
about ..." corner then you should think about doing some course.  Perhaps
there are evening classes in your area which will start at "beginners" and
then progress through "intermediate" and "advanced".  There are several
books on the subject starting with dummies guides.  Have a look at your book
shop or go to www.dummies.com.

If you are approaching this from a practical corner there is the Help
facility at F1.  More useful to you would be to use this NG to describe your
query.

If you are wanting to use excel to set something up for business then you
should, perhaps, speak to your local Excel support guy.

In essence, a formula is an 'argument' that says if this is true then do
this or, if not, do this.  Some formulae are quite extensive.  Indeed I have
had some which break the 256 character limit.  If you reflect back to
Algebra those elements within brackets are calculated first.  A double
brackets occur when there are two (or more) elements which need to be
calculated before another calculation.  There must always be an equal number
of "(" and ")" but Excel will prompt and sometimes even correct these
errors.  Some errors occur by the use of the arguments "AND" and "OR".  The
computer is precise in carrying out instructions and you can get some
bizarre results leading to some effort in debugging.  A trick in writing
formulae is always test each and every element against a known answer and
NEVER assume that it is 100% correct.

Hope that helps - a little at least!

Regards.

Bill Ridgeway
Computer Solutions