How to color a cell if equal to a value from a list?

Question

Google Sheets

The task is this - there are two columns with numbers. In the first set of numbers, in the second number in order. It is necessary to paint over the cells if the numbers are present in the first column. For example, the 1st column: 1, 2 second 1,2,3 Then paint over 1 and 2.
All this is done in Google spreadsheets and "Conditional Formatting" is engaged in changing the color and you can insert your formula there. Please tell me (A: A) the column does not work, (A1, A2) too.

Answer 1

Right now I can’t check in Excel, but in Libre I did this:
I set the name AAA to the desired search range
I set the condition for the first cell in the 1st column: IFERROR (VLOOKUP (A1; AAA; 1; 0); 0) and Red color
In Excel the analogue would be ISERROW(VLOOKUP(A1,AAA,1,0),0)
Then I copied the first cell, selected the first column -- Paste as -- Formats

Answer 2

Good advice from DanXai, but in general there are a lot of options for how to work with conditional formatting, I found a useful article here.