Huh?

Hi,

I don't quite understand what you want to do.  Let's suppose that the data
are in A1:A100.

If you want, B2 to be equal to A2-A1, B3 to be equal to A3-A2, ........,
B100 to be equal to A100-A99, enter the formula =A2-A1 in B2 and click ENTER.
B1 wil be blank.  Click again on B2, and autofill the formula down to B100
(for this, click on B2, move the cursor to the bottom right side corner of
the cell (the cursor will change into a "+" sign), hold the left-side mouse
button and drag down the rows to B100).

If you, on the other hand, want only ALTERNATE cells in column B (i.e., B2,
B4, B6, ... B100) show the difference between A values of the corresponding
and the previous rows (i.e., B1, B3, B5, ... B99 will be blank), do the
following.  Enter the same formula (i.e., =A2-A1) in B2.  Now select B1 and
B2, and autofill the column down to B100.  Now B2 will show A2-A1, B3 will be
blank, B4 will show A4-A3, B5 will be blank, B6 will show A6-A5, ..., and
.B100 will show A100-A99.

Regards,
B. R. Ramachandran