Why Numbers app chooses the wrong cells for simple sums on my MacBook?

Can't replicate here. Are you running the latest version, Numbers 14.4?

In general in Numbers you will find it more efficient to reference a whole column, e.g. SUM(B) rather than a range of cells within a column.

SG

Quite simply, because you're not trying to sum the selection. You are pointing to it.

To sum the cells, your formula in B16 should be:

=SUM(B5:B15)

So that Numbers knows to sum the values together and return the result.

When your formula is just:

=B5:B15

Numbers interprets that as "copy the cells B5 through B15 here", so it grabs those 11 cells and fills them in from B16 down. That's why those cells show a green hashed background - their values 'spill over' from the leading cell.

This may have changed in version 14.4, where Numbers added support for arrays and ranges.

Camelot wrote:

Quite simply, because you're not trying to sum the selection. You are pointing to it.

That's what I thought.

But when I tried it I found that Numbers 14.4 automatically supplies the missing SUM when selecting ("pointing to") a range as in the video.

You have to manually remove the automatically added SUM and ( ) in the formula editor before you can get the "spill" effect.

SUM works the same as before on my machine.

SG

> But when I tried it I found that Numbers 14.4 automatically supplies the missing SUM when selecting ("pointing to") a range as in the video.

I had to try this one again. Turns out we're both right, but it's subtle.

When I first read the OP, I could replicate the spill and noticed the problem (or, at least, the cause).

Now I try it again after your post and I'm getting the SUM(), too, but I didn't before.

Turns out there's a difference.

Select a cell, enter =, then click and drag over the range B5:B15 => SUM(B5:B15)

However:

Select a cell, enter =, select a reference cell B5, then drag the handle on B5 to drag down => =B5:B15

So there's a difference depending on whether you drag over the range (auto SUM()), or whether you click a cell and expand the selection (no auto SUM()).

Ah, now I can replicate.

In any case, Numbers SUM still works as expected.

SG