Need Help Please with Calculator Program

hello

Hope someone can help me. I have attached a zip file of my calculator program. What I am trying to do is and you will notice when you open the program, is put the input information from the click event (Top display text box- labelled txtInPut) from my number button clicks i.e 1,,3,4 etc.. to stay in the right side text Box labelled txtOutPut. I have put and equal button (=) to do the calculation (result). if I punch in 7+7 it shows 7+7 then display's the 14 in the right box. what I want it to do is I want to remove the = button and have what I calculate stay in the right box
for example: if I type in 7 * 7 I want it to format into the right box like so see ex 1. If I want to add or minus etc.. I want it to still show the inOutPut and the result see ex. 2

ex.1
7
7*
49

ex. 2
7
7*
49
10+
59
30-

I hope this makes sense, I f some one can tell me how to to keep the results in the right box I would be very thankful!

Thank you Kindly

Marcus Bell