LET /PROMPT

###
LET /PROMPT

            [SIC\]LET Variable [=] [Expression] /PROMPT "Explanatory text"
                    (GUI input mode and Command line mode)

        Create a text widget, with a specified prompt,  to  return  a  value  or
        valid  expression  for  the  variable. The text widget can be pre-loaded
        with an expression or value(s). Standard input will  be  available  once
        the widget is created by command GUI\GO.