Hello,
I use LS Versione 2.06+ Build 151215.
I am trying to add a question like this:

Q1. What is your net monthly income?
€ _ _ _ _ (999998 DK/NA)

Note that I have a range of 1-9999 for the income that can be easily assigned using Min and Max value in Advanced settings, and another value (999998), external to the range for the Don't Know/No answer.
I am asking if is there a way to set up a range of values in a numerical question so that a range of (n1-n2) + n3; n4; ... is accepted (where n3 and n4 are separate external values for Dont'know and No answer i.e., say 999998 and 999999).
In the case of a single value external to the range a possible solution would be to manage the 999998 option as the "Other" option, but numerical input question don't allow for such a possibility.
So... any suggestion is welcome!
Kind regards,
Elo

I think your only chance is doing this via regex.

Yes, you could use this for the Question validation equation. For clarification, this basically says:
- 1-9 followed by 0-3 instances of 0-9
OR
- 5 9s followed by either 8 or 9
And something like this for the Question validation tip:
Sample survey attached:

Thank you Holch and thank you Tpartner!
It works perfectly!
And given Q717 as question code, by using a simple expression I was able to set-up the range in this way:
(Q717 >= 1) && ((Q717 <= 9999) or (Q717 == 999998))) (--> Question Validation)

Cheers,
Elo