How do I display just the day of the week in Numbers app (sun, mon, etc)

Just :

1. select the cell
2. open the format bar on the rightand select the "Cell" tab
3. select Custom Format from the dropdown
4. click on edit custom format

you can choose "Sun" as the format option - or anythinig else you want.

I put this question in with the answer because an old question from someone else did not get the right answer (it was posted in 2013 so maybe things have changed)

The original post described wanting to get a date to display as just a day of the week like this “Sun” .

I have just done this. The method I described in my own answer works. If it isn’t clear, post again.