Here is a two-step solution hopefully:

1. Convert the numeric value into an integer

2. Create a text string with the integer in it.

Here is the little test:

One start variable: a numeric input with the value 4321.56

followed by:

I added the '<' and the '>' just for clarity in the output here.

Gives the result :

Thank you, @WouterT 

The 2 step process worked. 

It didn't occur to me to use the operation "Create a text string". I was originally using the action "Format number to string" and it added the comma thousands separator as well as the ".0" at the end.

I also tried skipping the "Convert a value" step, which converts the number to an integer. And that produced a string without the thousands separator, but the ".0" was still displayed.

So, the 2 step process is the winner. Thank you!