Maybe I miss-understand you?

But don't you just want to declare a signal in your header file. Then emit that signal when you get a signal (whichever you choose) from the Line edit object?

Like in your header:
Qt Code: 
  1. signals:
  2. void sendNewNumbersForMultiplication(QString ,QString );
To copy to clipboard, switch view to plain text mode 

Is this what you are trying to do?