I've been taking a certification course on Excel. It's a beginner class but something caught my attention. Specifically, **Data validation**.

We learned how to do it using the default conditions but I would like to include my own using formulas.

Here is where I'm at:

Now, what kind of formula would I put here? Would I use an `if`

? If so, what would I return? Would I return `TRUE`

or `FALSE`

?

I think the best way for me to learn would to be if somebody showed me an explicit example of one. So, for that purpose, here is a situation:

If B2 is exactly 28000, throw the validation error without using the default validation criteria. Thanks guys :)