Make an application that has a list of operators at the top, two operand input fields and one button for aktivacuju calculating results. Between the input field should be a field operator. The user has the possibility of drag from the top operators in the form field operator. When they enter the operands and operator, and pressed the button, the messagebox control (or another) appears the result of the calculation.
what do you want to make dear? By drag and drop you mean to drag and drop numbers and operators or only operators or you want to make a calculator control which you want to drop on your form?
for simple calculator you make buttons on form for input and textbox or label for displaying input and the result and at each button click event take the associated input. i think it is the simplest way any one can tell you. Assignments are given to you to get some learning and skills try it your self in any case of difficulty you can ask but not the whole code :)