Automatic update of numeric increment

Question

I use Excel 2013 but I do not know how to have a column with incremental numbers update automatically whenever I delete or add a row.

How can I achieve that?

Example

01
02
03
04

If I delete row 02, I would like that the program automatically sets the following row as 02 instead of 03, etc and if I add a row between 03 and 04, then that added row should show 04 automatically and 04 become 05 and so on.

Answer 1

Use =Row() or that plus an offset, if required.

Answer 2

You may write value as =, then address of upper cell (press up) and then +1. E.g. for cell B2 it would be =B1+1. Then hold mouse button on the bottom-right angle of that cell and drag mouse bottom as far as you need.