I am trying to set up a formula that will automatically give me a sum, adding
onto the number before it from the coumn beside.
EXAMPLE

Column C Column D
428 15491
2866 SUM
so what i want to do is to be able to punch in 2866 and press tab or enter
and in column D i want what was in Column C to add with what is in Column D
above it. If that makes any sense. I would like for 2866 to be added to
15491 sot hat where SUM is written, the sum of those two numbers would
appear. I want this to happen down the whole column with lots of different
number being punched it. Can someone please help me? I am really new to
excel but I have to work on it all day long at my new job.