IWork Numbers increase column size for sum

iworknumbers

If I have columns that sum at the bottom, how can I have the sum function automatically include a newly inserted row.

    a
  +---+
1 | 1 |
2 | 1 |
3 | 1 |
4 | 1 |
  +---+
  |=sum(a1:a4)|

Then when I add row 5 the sum function should be

=sum(a1:a5)

This functionality is embedded and its default behaviour. Of course if adding a row will be done using this option:

enter image description here

You are correct in that you need to use the SUMIF function. This is the specification from the Function Browser:

SUMIF(test-values, condition, sum-values)

Try this in your cell:

=SUMIF(CATEGORY; "=HW"; POINTS)

You can do this using header and footer rows. These automatically adjust the formulas contained within them based on the number of rows above.

The formula will automatically adjust from now on.

An animation for further explanation:

GIF