When in doubt, decompose (break into smaller parts) the problem!
You need to display a GUI. You need to accept input from two widgets and convert it integers. You need to add a range of numbers. You need to concatenate a string of what you're doing with the addition. You need to display an answer in a widget and maybe redraw the window.
I've been having success copying the assignment into my source file and decomposing it as comments to frame out my program.
