Hello all, I write in this forum because I have many doubts as to make the following graphical interface, my idea is to do something like the following:

and that as input parameters are the first number and second number order to operate on them subsequently. The problem is that it is not how to bind the boxes with the button to make the operation brought. I have done pieces of code for such an idea but without any results, here is what I have done

a=InputFiled[ ];
b=Inputfield[ ];
Button["Calculate",Print[Plus[a,b]
CheckboxBar[{1}, {1 -> "Plus", 2 -> "Subtract", 3 -> "Times",4-> "Division"}]

I hope that somebody can say me how to make my idea reality because it is the first time that I am doing this in Mathematica and and am having many problems.

Thanks in advance.