How to change a single number field in all rows to a negative value in a table?

I have a table that has a single column where every value needs to be changed to a negative.  Is there an easy way to do this?

Add a UI Only field to your model that executes a formula . {{MyField}}*-1

Then show that field in your table. 

I ran the field update off the UI field and it worked great.  Thanks.