I remember that feeling - I haven't been using formulas for very long.
Try this:
Cell A1 is "(fill in customer's name)"
Cell A2 is "Amount owed"
Cell A3 is "Balance due"
Cell B2 is the dollar amount the customer originally owed
Cell B3 is the following formula =B2-(SUM(E:E))
Cell D2 is "Payments"
Cell E2, E3, E4, etc are the payments
If you format columns as currency, you don't have to type in dollar signs
each time plus it will default to even dollar amounts.
Think back to math class when you were a kid and look at the formula. It'll
probably make sense. The (SUM(E:E)) part is telling Excel to add everything
in column E. Then subtract that from the number in cell B2. Oh - make sure
you start the formula with the equal sign.
It's not fancy but it will work for you. The important part is to make sure
the formula is written just that way. If you put the amount owed (cell B2)
in a different location, you have to change the formula. If you move the
payments to a different column (column E), you have to change the formula.
As long as you don't put any other numbers anywhere in that column, you'll
be fine.
--
JoAnn Paules
MVP Microsoft [Publisher]
Tech Editor for "Microsoft Publisher 2007 For Dummies"