As far as we know auto numbering will not work in merged cells. If you need to number a column that it is made up of different sized merged cells, when you try to drag the numbering it tries to resize the merge cells as well. Is there a way to number the merged cells without having to manually type the number?
For example, A1 is header, range A2:A15 is made up of different sized merged cells, see the following screen shot. How to fill number series in A2:A15?
We can use Excel formula to do it.
Step 1. Select the merged cells (in this example, select A2:A15).
Step 2. Press F2, or click the Formula Bar, enter the formula: =MAX(A$1:A1)+1.
Step 3. Press CTRL+ENTER.