Implementation of a calculator with a given object(calculator)

Hi All,
I am about to develop a calculator. My artist given me a calculator object, in that all the buttons are separate objects and calculator screen also separate. How do I write the code for it for accessing all the buttons with over the screen.can I use GUI text for accessing calculator.? If so let me know the procedure behind it.

Ok I guess your question is not about making calculation but about how to get the pressed button.

Two ways that I know.

First use GUI.Button. You would have to create a GUIStyle for each button or a GUISkin for the whole thing , and pass the corresponding style/skin index.

GUIStyle button1 = new GUIStyle();
GUIStyle button2 = new GUIStyle();
public Texture2D texture1;
public Texture2D texture2;

void Start(){
    button1.normal.background = texture1;
    button2.normal.background = texture2;
}

void OnGUI(){
    if(GUI.Button(positionRect1,"",style1)){}
    if(GUI.Button(positionRect2,"",style2)){}
}

The other way is to use planes to which you pass the texture and then you use a basic raycast and check. You would manually place them in the environment.

RaycastHit hit;
public Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
if (Physics.Raycast(ray, out hit, 100)){
    if(hit.collider.tag == "Button1"){}
    if(hit.collider.tag == "Button2"){}
}