Using Excel 2003 and am still having trouble getting a formula to extend to
new rows. I ran a trial formula that simple adds the number in A1 to the
number in B1 and puts the result in C1. I copied that formula down five
rows and filled data into Column A and Column B. When I added new rows, the
formula extended into the new rows just perfectly.

Then I ran a different trial formula. I entered a number into C1 and I put
a number in A2 and a number in B2. The formula I built in C3 was to start
with the number in C1, add the number in A2 and subtract the number in B2.
The formula works just fine and works just fine when I copy it down five
rows and fill data into Column A and Column B.

What does NOT happen is that when I add a new row of data with a number in
Column A and a number in Column B, the formula does not automatically extend
to produce a new result in Column C.

Can someone tell me what I'm missing???