Help text for "Calculation formula"

[fatso83]

Is your feature request related to a problem? Please describe.
I am having trouble understanding what the "Calculation formula" in the Advanced Settings of a "Number with unit" question type is supposed to do and how to use it.

Describe the solution you'd like
A helper text with an example or to some documentation.

[KimHoelHalvorsen]

Hello. We will add a short description for this field, but will take som time.