How can we add dollar sign ($) before calculation?

I tried to do as directed it as shown with the $ as the first entry, but it doesn't work

The same steps still apply as on the previous thread, so it would be best if you can tell us what is the form and how you want the same to work.

That will allow us to properly assist you and guide you how you can do the same with the sample and to see what might have happened when you were adding it yourself.