Creating an Addition Tutor in Visual Basic

In Visual Basic the form needs to contain one command button that should present a new addition problem and one should allow the user to quit. There should be a text box to present the question and accept the answer and another to tell the user whether her answer was correct. End program with the quit button. After that is working, add option buttons to allow the user to choose easy medium or hard problems, i.e., numbers between 0 and 9, 0 and 99 or 0 and 999.
My question is the following: To create an new problem in the text box, what should the code look like in the command button? I know that x=int(random()*10) and y=int(random()*10) but I am having a tough time putting it together to show the problem in the text box. Thank you!