<?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/enterSolution"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginTop="32dp"
        android:layout_marginEnd="16dp"
        android:ems="10"
        android:inputType="number"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/equation" />

    <Button
        android:id="@+id/checkAnswer"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginBottom="8dp"
        android:background="#b3e5fc"
        android:onClick="checkAnswer"
        android:text="@string/check_answer"
        app:layout_constraintBottom_toTopOf="@+id/nextSum"
        app:layout_constraintStart_toStartOf="parent" />

    <TextView
        android:id="@+id/numberOne"
        android:layout_width="100dp"
        android:layout_height="50dp"
        android:layout_marginStart="16dp"
        android:layout_marginTop="32dp"
        android:background="#e0e0e0"
        android:text="@string/numberOne"
        android:textAlignment="center"
        android:textSize="36sp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/equation"
        android:layout_width="100dp"
        android:layout_height="50dp"
        android:layout_marginStart="16dp"
        android:layout_marginTop="32dp"
        android:layout_marginEnd="16dp"
        android:background="#e0e0e0"
        android:textAlignment="center"
        android:textSize="36sp"
        app:layout_constraintEnd_toStartOf="@+id/numberTwo"
        app:layout_constraintStart_toEndOf="@+id/numberOne"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/numberTwo"
        android:layout_width="100dp"
        android:layout_height="50dp"
        android:layout_marginTop="32dp"
        android:layout_marginEnd="16dp"
        android:background="#e0e0e0"
        android:text="@string/numberTwo"
        android:textAlignment="center"
        android:textSize="36sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/nextSum"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginBottom="32dp"
        android:background="#b3e5fc"
        android:onClick="newSum"
        android:text="@string/next_sum"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintStart_toStartOf="parent" />

</android.support.constraint.ConstraintLayout>