Can you help me with this please - I used to think I knew a little bit about
Excel.

The problem showed up when I wrote a golf scorecard spreadsheet, but the
essence of it is this:

I entered the numbers 1,2,3,4 in cells A1 to D1. In F1 I put the formula
sum(A1:D1). Answer 10. So far so good. But if you enter say the value 5 in
E1, the formula dynamically alters to sum(A1:E1) and the result changes to 15.

If it's some kind of 'intelli' option I've got set, then I can't find it.
Why is the above effect occurring, and how can I stop it? I'm on Excel 2000.


Thanks,
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N