I have a spreadsheet to maintain truck weights.

If the weighmaster enters a Gross, and a Secondary Gross, the spreadsheet
should calculate the amount of shrink (Gross - Secondary Gross).

If the weighmaster enters ONLY a Gross and a Tare weight, the spreadsheet
should give an ESTIMATED shrink calculation, then show the result of Gross -
Estimated Shrink in the Secondary Gross column.

How can I do this??? Only way I could think of is with some way to
determine whether Secondary Gross column cell contains a USER ENTERED NUMBER,
or still has the formula to arrive at the ESTIMATED secondary weight. If
Secondary Gross has a formula, then Shrink should be Gross * .005, and
Secondary Gross should show result of Gross - Shrink.

If BOTH Gross AND Secondary Gross cells contain user entered numbers, Shrink
should contain result of Gross - Secondary Gross.

Btw... My employer has Excel 2000. So please, if you have a solution, try
to make it one I can implement in Excel 2000.