Rule to automatically highlight cells if within a certain amount

Hi,

How can I create a rule to automatically highlight/fill a cell (let's say, the yellow color) whose calculated value is within a certain range ?

For example, let's say I have a cell whose value is generated from the addition or subtraction of other cells,
and if the resulting number is negative, I want that cell to automatically be highlighted so as to make it easier to see on a large spreadsheet with lots of data.

Thank you.