Excel reference current cell for conditional formatting

Question

So here's my problem. I have a table of the numbers 1 through 100, and another cell (we'll call it A1) that will contain a number between 1 and 100. I would like to use conditional formatting to fill these cells, so if A1 contains the number 20, all of the cells from 1 to 20 will be filled. I am trying to use conditional formatting in order to achieve this, and would like to use the format painter if possible to make this easier (instead of making a new rule each time). I feel that the best way to accomplish this is to reference the current cell, i.e. format if CURRENT_CELL <= A1. I am struggling to reference the current cell.

Answer 1

You can use the Less Then and the Equal conditional formatting like you can see below.

There is no need for a custom rules.