Android : I want to make equation between two Edit text

I want to make equation between two edit text and put the output on Toast I tried to use that way : String data1 = one.getText().toString(); String data2 = two.getText().toString(); String RES = data1 + data2; but this way outputted result as String not numbers Find code below : Main Activity code : MainActivity.java

package com.mkadaim.android;

import android.R.integer;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.text.Editable;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

 public class MainActivity extends ActionBarActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);


    final EditText one = (EditText)findViewById(R.id.First);
    final EditText two = (EditText)findViewById(R.id.Second);

    Button res = (Button)findViewById(R.id.Result);
    res.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
        int x = one.getText();
        int y = two.getText();
        int z = x + y;
        Toast.makeText(getBaseContext(), z, 4000).show();

        }
    });
}


}