I've got a question about a macro. It should function in a Win XP
environment with Office 2000.
I'd like to know how to construct a macro to do what follows:
First of all, I need a macro that will delete any number that appears
more than once (mostly twice) in a very extensive list. I'd rather not
do this manually.

The second question is about comparing two sheets of different
workbooks.
I need to mark numbers that appear on the second sheet, but not on the
first to be marked in a specific color, but only this way, not the
other way around.
The third thing I need is a macro (?) to add numbers that appear in
the first sheet to be added to the second.

This may seem a rather extensive set of questions.
On the other hand it may seem macros that are rather easy to
construct, but I am just a newbie in VBA.

I'd appreciate any help. If it's not possible to do so, that's ok too.
I'd just like to know if it's possible and if so how.