UI Text Editing Problem, What's Wrong? Need Anybody to Assist

Hi there, I am extremely new here (just about 2 weeks) and this is my first attempt to create game ! I would like to say Hi too for every expert here. Hope I can be like you all, soon :)

So here's my problem. I have completed all of the stuff (options, UI, splash,etc) and now I have problem in the core game itself. I need help so when people tap or click a UI button named '0', in the "Text Here" field will write 0 , then if tap '1' two times, it will show '11', etc. I know it's very simple stuff for you all but I have tried using GUIText at first (but not working), then someone told me that I need to use Text instead in new UI system.

Here's what I've tried in UI. So I declared this,

 public int ansText;
 public static GameObject answerText;

Then tried to spot AnswerText gameObject (which is the UI text)

 answerText = GameObject.Find("AnswerText");

then use this functions,

 public void OnClickNumber(){
         answerText.GetComponent<Text>().text = "" + ansText;
         answerText.GetComponent<Text>().text = ansText.ToString();
   }

to use, I input each OnClick() button with this function, OnClickNumber() . Then each int value, I assigned desired value, like 0 for 0 , etc.

So, in which part I did wrong? I couldn't find any clue, have spent hours too play around with the code but no luck. :( I have almost give up, if anyone can assist me in Skype or Teamviewer that would be great.

skype: just4kamil

Thanks in advance.