How to change cell background color in numbers according to some rules?

Making it simple, using Numbers, how can you set up the following:

If number is positive make background cell green, else make it red.


Solution 1:

Select the cell where you want to apply the rule. From the menu choose Format -> Show Conditional Format rules. A window opens which allows you to enter rules.

For example (this is the rule you asked for): enter image description here