How do I divide the summary's evaluated value in formula instead of it's row?

Hello, I am creating a Saved Search using formulas to divide two Transaction Body fields containing a formula.

Let's call this Field A:

ABS(CASE WHEN {quantity}<0  THEN {quantity} ELSE 0 END)

Let's call this Field B:

CASE WHEN {quantity}>0  THEN {quantity} ELSE 0 END

Here is what I am attempting to do with these two formulas:

Field A / Field B

This is the summary page of my item saved search:

As you may have figured from the given two formulas, I would receive an error because when I click the Inventory Item, the transactions that make up this number is always divided by zero. The zero is entered from the ELSE statement. Field A is a positive quantity integer of sold items. Field B is a negative quantity integer turned into a positive number to indicate items returned.