Unable to subtract one cell from another in Numbers app

When odd things happen I look for oddities in what has been posted. One oddity is the formula results.

O87 is $15,750

O88 is $7,685.

The formula you provided in your first post for cell Q89 was =Q87-Q88 which leads me to think the formula for O89 would be =O87-O88 but the result there would be $8,065 not -$23,435. Is O89 a different formula?

Back to the question, though...

With cell Q89 selected, what does it say at the bottom of the window? Does it show your formula?

If you double click the cell to bring up the formula editor, it should give the formula result at the bottom of the screen. Is it correct?

With the cell selected, what is the text color shown in the format sidebar? You posted the data format (currency) and fill color (none) from the "Cell" tab but not the text color in the "Text" tab.

Are the screenshots you posted of the cell formatting and conditional highlighting those of cell Q89? It looks like cell O89 is selected and you talk about O89, which made it a little confusing.

Your formula is about as straightforward as it gets, so I can see why you're confused.

I an only think of two things that would cause this.

One is conditional formatting, that's set to mask the result if it's negative

(check Inspector -> Format -> Cell -> Conditional Formatting with the cell selected).

The other is a custom data format that suppresses negative values.

(check Inspector -> Format -> Cell -> Data Format -> Custom Format). As an example, here's a custom format that nixes non-positive values:

The latter would be easy to test by changing either changing the cell format to the standard 'Currency', or edit the formula to subtract the smaller number from the larger one. That would at least give a positive value and may indicate the format as being the issue.

There is no "closed". We used to be able to mark a post as "solved" to indicate no more help was needed, but we no longer have that ability. This thread will fade into the background as newer threads come along.