Android Code

main-activity.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <EditText
        android:id="@+id/editTextNumber"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:ems="10"
        android:inputType="number"
        android:hint="Please Enter Number"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.442"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.107" />

    <EditText
        android:id="@+id/editTextNumber2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:ems="10"
        android:inputType="number"
        android:hint="Please Enter Number"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.442"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.224" />

    <Button
        android:id="@+id/button"
        android:layout_width="116dp"
        android:layout_height="58dp"
        android:onClick="addNumber"
        android:text="Add"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.244"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.396"
        android:background="#FF009688"
        android:textColor="@color/white"
        />

    <Button
        android:id="@+id/button2"
        android:layout_width="116dp"
        android:layout_height="58dp"
        android:onClick="subtractNumber"
        android:text="Subtract"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.728"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.396"
        android:background="#FF009688"
        android:textColor="@color/white"
        />

    <Button
        android:id="@+id/button3"
        android:layout_width="116dp"
        android:layout_height="58dp"
        android:onClick="multiplyNumber"
        android:text="Multiply"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.244"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.55"
        android:background="#FF009688"
        android:textColor="@color/white"
        />

    <Button
        android:id="@+id/button4"
        android:layout_width="116dp"
        android:layout_height="58dp"
        android:onClick="dividedNumber"
        android:text="Divide"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.728"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.549"
        android:background="#FF009688"
        android:textColor="@color/white"
        />

    <EditText
        android:id="@+id/editTextNumber3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="508dp"
        android:ems="10"
        android:inputType="number"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.442"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/button6"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Clear"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.458"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.891"
        android:background="#F44336"
        android:textColor="@color/white"
        />

</android.support.constraint.ConstraintLayout>

MainActivity.java

package com.example.mahekarim162_15_7770;

import android.graphics.Color;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class MainActivity extends AppCompatActivity {

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


    }

    public void addNumber(View v) {
        EditText et1 = (EditText)findViewById(R.id.editTextNumber);
        EditText et2 = (EditText)findViewById(R.id.editTextNumber2);
        EditText et3 = (EditText)findViewById(R.id.editTextNumber3);
//        Button eth4 = (Button)findViewById(R.id.button);
//        et4.setBackgroundColor(Color.rgb(0, 84, 119));  n


        int n1 = Integer.parseInt(et1.getText().toString());
        int n2 = Integer.parseInt(et2.getText().toString());

        int result = n1 + n2 ;
        et3.setText("The added value is " + result);
    }

    public void subtractNumber(View v) {
        EditText et1 = (EditText)findViewById(R.id.editTextNumber);
        EditText et2 = (EditText)findViewById(R.id.editTextNumber2);
        EditText et3 = (EditText)findViewById(R.id.editTextNumber3);

        int n1 = Integer.parseInt(et1.getText().toString());
        int n2 = Integer.parseInt(et2.getText().toString());

        int result = n1 - n2 ;
        et3.setText("The added value is " + result);
    }

    public void multiplyNumber(View v) {
        EditText et1 = (EditText)findViewById(R.id.editTextNumber);
        EditText et2 = (EditText)findViewById(R.id.editTextNumber2);
        EditText et3 = (EditText)findViewById(R.id.editTextNumber3);

        int n1 = Integer.parseInt(et1.getText().toString());
        int n2 = Integer.parseInt(et2.getText().toString());

        int result = n1 * n2 ;
        et3.setText("The added value is " + result);
    }

    public void dividedNumber(View v) {
        EditText et1 = (EditText)findViewById(R.id.editTextNumber);
        EditText et2 = (EditText)findViewById(R.id.editTextNumber2);
        EditText et3 = (EditText)findViewById(R.id.editTextNumber3);

        float n1 = Float.parseFloat(et1.getText().toString());
        float n2 = Float.parseFloat(et2.getText().toString());

        Float result = n1 / n2 ;
        et3.setText("The added value is " + result);

    }

    public void clearButton() {

    }
}