diff --git a/lab-01/src/by/dudkoandrei/quizer/Main.java b/lab-01/src/by/dudkoandrei/quizer/Main.java
new file mode 100644
index 0000000..e51952a
--- /dev/null
+++ b/lab-01/src/by/dudkoandrei/quizer/Main.java
@@ -0,0 +1,73 @@
+package by.dudkoandrei.quizer;
+
+import by.dudkoandrei.quizer.constants.EquationTaskGeneratorConstants;
+import by.dudkoandrei.quizer.constants.ExpressionTaskGeneratorConstants;
+import by.dudkoandrei.quizer.constants.TextGeneratorConstats;
+import by.dudkoandrei.quizer.task_generators.GroupTaskGenerator;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Scanner;
+
+public class Main {
+
+  /**
+   * @return тесты в {@link Map}, где ключ - название теста {@link String} значение - сам тест
+   * {@link Quiz}
+   */
+  static Map<String, Quiz> getQuizMap() {
+    Map<String, Quiz> quizMap = new HashMap<>();
+
+    quizMap.put("Text Quiz", new Quiz(TextGeneratorConstats.generator, 3));
+    quizMap.put("Integer equations", new Quiz(EquationTaskGeneratorConstants.integerGenerator, 10));
+    quizMap.put("Equations", new Quiz(EquationTaskGeneratorConstants.generator, 10));
+    quizMap.put("Integer expressions",
+        new Quiz(ExpressionTaskGeneratorConstants.integerGenerator, 10));
+    quizMap.put("Expressions", new Quiz(ExpressionTaskGeneratorConstants.generator, 10));
+    quizMap.put("All tasks", new Quiz(
+        new GroupTaskGenerator(TextGeneratorConstats.generator,
+            EquationTaskGeneratorConstants.integerGenerator,
+            EquationTaskGeneratorConstants.generator,
+            ExpressionTaskGeneratorConstants.integerGenerator,
+            ExpressionTaskGeneratorConstants.generator), 20));
+
+    return quizMap;
+  }
+
+  public static void main(String[] args) {
+    Scanner scanner = new Scanner(System.in);
+
+    var quizMap = getQuizMap();
+
+    System.out.println("Available quizzes:");
+
+    for (var name : quizMap.keySet()) {
+      System.out.println(name);
+    }
+
+    System.out.println("Select quiz:");
+
+    String name = scanner.nextLine();
+    while (!quizMap.containsKey(name)) {
+      System.out.println("No such quiz. Try again");
+      name = scanner.nextLine();
+    }
+
+    Quiz quiz = quizMap.get(name);
+
+    System.out.println("Quiz: \"" + name + "\" started");
+    while (!quiz.isFinished()) {
+      System.out.println(quiz.nextTask().getText());
+
+      String answer = scanner.nextLine();
+      Result result = quiz.provideAnswer(answer);
+
+      System.out.println(result + "\n");
+    }
+
+    System.out.println("Quiz ended");
+    System.out.println("Your score: " + quiz.getMark() * 10);
+    System.out.println("Correct answers: " + quiz.getCorrectAnswerNumber());
+    System.out.println("Wrong answers: " + quiz.getWrongAnswerNumber());
+    System.out.println("Incorrect input: " + quiz.getIncorrectInputNumber());
+  }
+}
diff --git a/lab-01/src/by/dudkoandrei/quizer/Quiz.java b/lab-01/src/by/dudkoandrei/quizer/Quiz.java
new file mode 100644
index 0000000..f4b5a03
--- /dev/null
+++ b/lab-01/src/by/dudkoandrei/quizer/Quiz.java
@@ -0,0 +1,119 @@
+package by.dudkoandrei.quizer;
+
+import by.dudkoandrei.quizer.exceptions.QuizFinishedException;
+import by.dudkoandrei.quizer.exceptions.QuizNotFinishedException;
+import by.dudkoandrei.quizer.tasks.Task;
+
+/**
+ * Class, который описывает один тест.
+ */
+class Quiz {
+
+  private final Task.Generator taskGenerator;
+
+  private Task currentTask = null;
+  private final int taskCount;
+  private boolean answeredOnCurrentTask = false;
+  private int correctAnswerNumber = 0;
+  private int wrongAnswerNumber = 0;
+  private int incorrectInputNumber = 0;
+
+  /**
+   * @param generator генератор заданий
+   * @param taskCount количество заданий в тесте
+   */
+  Quiz(Task.Generator generator, int taskCount) {
+    if (taskCount <= 0) {
+      throw new IllegalArgumentException("Task count should be positive");
+    }
+    if (generator == null) {
+      throw new IllegalArgumentException("Generator is null");
+    }
+    this.taskGenerator = generator;
+    this.taskCount = taskCount;
+  }
+
+  /**
+   * @return задание, повторный вызов вернет слелующее
+   * @see Task
+   */
+  Task nextTask() {
+    if (isFinished()) {
+      throw new QuizFinishedException();
+    }
+
+    if (answeredOnCurrentTask || currentTask == null) {
+      currentTask = taskGenerator.generate();
+      answeredOnCurrentTask = false;
+    }
+
+    return currentTask;
+  }
+
+  /**
+   * Предоставить ответ ученика. Если результат {@link Result#INCORRECT_INPUT}, то счетчик
+   * неправильных ответов не увеличивается, а {@link #nextTask()} в следующий раз вернет тот же
+   * самый объект {@link Task}.
+   */
+  Result provideAnswer(String answer) {
+    if (isFinished()) {
+      throw new QuizFinishedException();
+    }
+
+    Result result = currentTask.validate(answer);
+
+    switch (result) {
+      case OK -> {
+        correctAnswerNumber++;
+        answeredOnCurrentTask = true;
+      }
+      case WRONG -> {
+        wrongAnswerNumber++;
+        answeredOnCurrentTask = true;
+      }
+      case INCORRECT_INPUT -> incorrectInputNumber++;
+    }
+
+    return result;
+  }
+
+  /**
+   * @return завершен ли тест
+   */
+  boolean isFinished() {
+    return correctAnswerNumber + wrongAnswerNumber == taskCount;
+  }
+
+  /**
+   * @return количество правильных ответов
+   */
+  int getCorrectAnswerNumber() {
+    return correctAnswerNumber;
+  }
+
+  /**
+   * @return количество неправильных ответов
+   */
+  int getWrongAnswerNumber() {
+    return wrongAnswerNumber;
+  }
+
+  /**
+   * @return количество раз, когда был предоставлен неправильный ввод
+   */
+  int getIncorrectInputNumber() {
+    return incorrectInputNumber;
+  }
+
+  /**
+   * @return оценка, которая является отношением количества правильных ответов к количеству всех
+   * вопросов. Оценка выставляется только в конце!
+   */
+  double getMark() {
+    if (!isFinished()) {
+      throw new QuizNotFinishedException();
+    }
+
+    return ((double) correctAnswerNumber) / taskCount;
+  }
+}
diff --git a/lab-01/src/by/dudkoandrei/quizer/Result.java b/lab-01/src/by/dudkoandrei/quizer/Result.java
new file mode 100644
index 0000000..f024e8c
--- /dev/null
+++ b/lab-01/src/by/dudkoandrei/quizer/Result.java
@@ -0,0 +1,10 @@
+package by.dudkoandrei.quizer;
+
+/**
+ * Enum, который описывает результат ответа на задание.
+ */
+public enum Result {
+  OK, // Получен правильный ответ
+  WRONG, // Получен неправильный ответ
+  INCORRECT_INPUT // Некорректный ввод. Например, текст, когда ожидалось число
+}
diff --git a/lab-01/src/by/dudkoandrei/quizer/constants/EquationTaskGeneratorConstants.java b/lab-01/src/by/dudkoandrei/quizer/constants/EquationTaskGeneratorConstants.java
new file mode 100644
index 0000000..aa76ddd
--- /dev/null
+++ b/lab-01/src/by/dudkoandrei/quizer/constants/EquationTaskGeneratorConstants.java
@@ -0,0 +1,19 @@
+package by.dudkoandrei.quizer.constants;
+
+import by.dudkoandrei.quizer.tasks.Task.Generator;
+import by.dudkoandrei.quizer.tasks.math_tasks.EquationTask;
+import by.dudkoandrei.quizer.tasks.math_tasks.MathTask.Operation;
+import java.util.EnumSet;
+
+public class EquationTaskGeneratorConstants {
+
+  public static final Generator generator = new EquationTask.Generator(
+      0,
+      25,
+      4,
+      EnumSet.allOf(Operation.class));
+  public static final Generator integerGenerator = new EquationTask.Generator(
+      0,
+      25,
+      EnumSet.allOf(Operation.class));
+}
diff --git a/lab-01/src/by/dudkoandrei/quizer/constants/ExpressionTaskGeneratorConstants.java b/lab-01/src/by/dudkoandrei/quizer/constants/ExpressionTaskGeneratorConstants.java
new file mode 100644
index 0000000..4a0bde9
--- /dev/null
+++ b/lab-01/src/by/dudkoandrei/quizer/constants/ExpressionTaskGeneratorConstants.java
@@ -0,0 +1,19 @@
+package by.dudkoandrei.quizer.constants;
+
+import by.dudkoandrei.quizer.tasks.Task.Generator;
+import by.dudkoandrei.quizer.tasks.math_tasks.ExpressionTask;
+import by.dudkoandrei.quizer.tasks.math_tasks.MathTask.Operation;
+import java.util.EnumSet;
+
+public class ExpressionTaskGeneratorConstants {
+
+  public static final Generator generator = new ExpressionTask.Generator(
+      0,
+      25,
+      4,
+      EnumSet.allOf(Operation.class));
+  public static final Generator integerGenerator = new ExpressionTask.Generator(
+      0,
+      25,
+      EnumSet.allOf(Operation.class));
+}
diff --git a/lab-01/src/by/dudkoandrei/quizer/constants/TextGeneratorConstats.java b/lab-01/src/by/dudkoandrei/quizer/constants/TextGeneratorConstats.java
new file mode 100644
index 0000000..3fc3f9d
--- /dev/null
+++ b/lab-01/src/by/dudkoandrei/quizer/constants/TextGeneratorConstats.java
@@ -0,0 +1,26 @@
+package by.dudkoandrei.quizer.constants;
+
+import by.dudkoandrei.quizer.task_generators.PoolTaskGenerator;
+import by.dudkoandrei.quizer.tasks.Task.Generator;
+import by.dudkoandrei.quizer.tasks.TextTask;
+
+public class TextGeneratorConstats {
+
+  public static final Generator generator = new PoolTaskGenerator(
+      false,
+      new TextTask("Fill in the blank: \"_____. I'm your father.\"\n"
+          + "a) Luke\n"
+          + "b) Boy\n"
+          + "c) Skywalker\n"
+          + "d) No", "d"),
+      new TextTask("Mace Windu light-saber color?\n"
+          + "a) Red\n"
+          + "b) Purple\n"
+          + "c) Green\n"
+          + "d) Blue", "b"),
+      new TextTask("What species of alien is Yoda?\n"
+          + "a) Ortolan\n"
+          + "b) Human\n"
+          + "c) Unknown\n"
+          + "d) Gungan", "c"));
+}
diff --git a/lab-01/src/by/dudkoandrei/quizer/exceptions/GeneratorsFailedException.java b/lab-01/src/by/dudkoandrei/quizer/exceptions/GeneratorsFailedException.java
new file mode 100644
index 0000000..f8f1c39
--- /dev/null
+++ b/lab-01/src/by/dudkoandrei/quizer/exceptions/GeneratorsFailedException.java
@@ -0,0 +1,8 @@
+package by.dudkoandrei.quizer.exceptions;
+
+public class GeneratorsFailedException extends RuntimeException {
+
+  public GeneratorsFailedException() {
+    super("All generators threw exceptions");
+  }
+}
diff --git a/lab-01/src/by/dudkoandrei/quizer/exceptions/NoMoreTasksException.java b/lab-01/src/by/dudkoandrei/quizer/exceptions/NoMoreTasksException.java
new file mode 100644
index 0000000..a7ee9b1
--- /dev/null
+++ b/lab-01/src/by/dudkoandrei/quizer/exceptions/NoMoreTasksException.java
@@ -0,0 +1,8 @@
+package by.dudkoandrei.quizer.exceptions;
+
+public class NoMoreTasksException extends RuntimeException {
+
+  public NoMoreTasksException() {
+    super("No more tasks");
+  }
+}
diff --git a/lab-01/src/by/dudkoandrei/quizer/exceptions/QuizFinishedException.java b/lab-01/src/by/dudkoandrei/quizer/exceptions/QuizFinishedException.java
new file mode 100644
index 0000000..31dd763
--- /dev/null
+++ b/lab-01/src/by/dudkoandrei/quizer/exceptions/QuizFinishedException.java
@@ -0,0 +1,8 @@
+package by.dudkoandrei.quizer.exceptions;
+
+public class QuizFinishedException extends RuntimeException {
+
+  public QuizFinishedException() {
+    super("Quiz is finished");
+  }
+}
diff --git a/lab-01/src/by/dudkoandrei/quizer/exceptions/QuizNotFinishedException.java b/lab-01/src/by/dudkoandrei/quizer/exceptions/QuizNotFinishedException.java
new file mode 100644
index 0000000..b166049
--- /dev/null
+++ b/lab-01/src/by/dudkoandrei/quizer/exceptions/QuizNotFinishedException.java
@@ -0,0 +1,8 @@
+package by.dudkoandrei.quizer.exceptions;
+
+public class QuizNotFinishedException extends RuntimeException {
+
+  public QuizNotFinishedException() {
+    super("Quiz is not finished");
+  }
+}
diff --git a/lab-01/src/by/dudkoandrei/quizer/task_generators/GroupTaskGenerator.java b/lab-01/src/by/dudkoandrei/quizer/task_generators/GroupTaskGenerator.java
new file mode 100644
index 0000000..c987ebd
--- /dev/null
+++ b/lab-01/src/by/dudkoandrei/quizer/task_generators/GroupTaskGenerator.java
@@ -0,0 +1,73 @@
+package by.dudkoandrei.quizer.task_generators;
+
+import by.dudkoandrei.quizer.exceptions.GeneratorsFailedException;
+import by.dudkoandrei.quizer.tasks.Task;
+import by.dudkoandrei.quizer.tasks.Task.Generator;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * Task.Generator, который позволяет объединить несколько других Task.Generator.
+ */
+public class GroupTaskGenerator implements Task.Generator {
+
+  private final List<Generator> generators;
+  private int lastGeneratorIndex = 0;
+
+  /**
+   * Конструктор с переменным числом аргументов.
+   *
+   * @param generators генераторы, которые в конструктор передаются через запятую
+   */
+  public GroupTaskGenerator(Task.Generator... generators) {
+    this(Arrays.asList(generators));
+  }
+
+  /**
+   * Конструктор, который принимает коллекцию генераторов.
+   *
+   * @param generators генераторы, которые передаются в конструктор в Collection (например,
+   *                   {@link ArrayList})
+   */
+  public GroupTaskGenerator(Collection<Generator> generators) {
+    if (generators == null) {
+      throw new IllegalArgumentException("generators is null");
+    }
+    if (generators.isEmpty()) {
+      throw new IllegalArgumentException("generators is empty");
+    }
+    if (generators.contains(null)) {
+      throw new IllegalArgumentException("generators contains null");
+    }
+
+    this.generators = new ArrayList<>(generators);
+
+    Collections.shuffle(this.generators);
+  }
+
+  /**
+   * @return результат метода generate() случайного генератора из списка. Если этот генератор
+   * выбросил исключение в методе generate(), выбирается другой. Если все генераторы выбрасывают
+   * исключение, то и тут выбрасывается исключение.
+   */
+  public Task generate() {
+    for (int offset = 1; offset <= generators.size(); ++offset) {
+      try {
+        int index = getGeneratorIndex(offset);
+        Task t = generators.get(index).generate();
+        lastGeneratorIndex = index;
+        return t;
+      } catch (Exception ignored) {
+      }
+    }
+
+    throw new GeneratorsFailedException();
+  }
+
+  private int getGeneratorIndex(int offset) {
+    return (lastGeneratorIndex + offset) % generators.size();
+  }
+}
diff --git a/lab-01/src/by/dudkoandrei/quizer/task_generators/PoolTaskGenerator.java b/lab-01/src/by/dudkoandrei/quizer/task_generators/PoolTaskGenerator.java
new file mode 100644
index 0000000..9681ad1
--- /dev/null
+++ b/lab-01/src/by/dudkoandrei/quizer/task_generators/PoolTaskGenerator.java
@@ -0,0 +1,77 @@
+package by.dudkoandrei.quizer.task_generators;
+
+import by.dudkoandrei.quizer.exceptions.NoMoreTasksException;
+import by.dudkoandrei.quizer.tasks.Task;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Random;
+import java.util.stream.Collectors;
+
+/**
+ * Task.Generator, который отдает задания из заранее заготовленного набора.
+ */
+public class PoolTaskGenerator implements Task.Generator {
+
+  private final List<Task> tasks;
+  private final boolean allowDuplicate;
+  private int currentPosition = 0;
+  private static final Random rnd = new Random();
+
+  /**
+   * Конструктор с переменным числом аргументов.
+   *
+   * @param allowDuplicate разрешить повторения
+   * @param tasks          задания, которые в конструктор передаются через запятую
+   */
+  public PoolTaskGenerator(boolean allowDuplicate, Task... tasks) {
+    this(allowDuplicate, Arrays.asList(tasks));
+  }
+
+  /**
+   * Конструктор, который принимает коллекцию заданий.
+   *
+   * @param allowDuplicate разрешить повторения
+   * @param tasks          задания, которые передаются в конструктор в Collection (например,
+   *                       {@link LinkedList})
+   */
+  public PoolTaskGenerator(boolean allowDuplicate, Collection<Task> tasks) {
+    if (tasks == null) {
+      throw new IllegalArgumentException("tasks is null");
+    }
+    if (tasks.isEmpty()) {
+      throw new IllegalArgumentException("tasks is empty");
+    }
+    if (tasks.contains(null)) {
+      throw new IllegalArgumentException("tasks contains null");
+    }
+
+    this.allowDuplicate = allowDuplicate;
+
+    if (!allowDuplicate) {
+      this.tasks = tasks.stream().distinct().collect(Collectors.toList());
+    } else {
+      this.tasks = new ArrayList<>(tasks);
+    }
+
+    Collections.shuffle(this.tasks);
+  }
+
+  /**
+   * @return случайная задача из списка
+   */
+  public Task generate() {
+    if (allowDuplicate) {
+      return tasks.get(rnd.nextInt(tasks.size()));
+    }
+
+    if (currentPosition == tasks.size()) {
+      throw new NoMoreTasksException();
+    }
+
+    return tasks.get(currentPosition++);
+  }
+}
diff --git a/lab-01/src/by/dudkoandrei/quizer/tasks/Task.java b/lab-01/src/by/dudkoandrei/quizer/tasks/Task.java
new file mode 100644
index 0000000..542a9b3
--- /dev/null
+++ b/lab-01/src/by/dudkoandrei/quizer/tasks/Task.java
@@ -0,0 +1,40 @@
+package by.dudkoandrei.quizer.tasks;
+
+import by.dudkoandrei.quizer.Result;
+
+/**
+ * Interface, который описывает одно задание.
+ */
+public interface Task {
+
+  /**
+   * Interface, который описывает один генератор заданий.
+   */
+  interface Generator {
+
+    /**
+     * Возвращает задание. При этом новый объект может не создаваться, если класс задания
+     * иммутабельный.
+     *
+     * @return задание
+     * @see Task
+     */
+    Task generate();
+  }
+
+  /**
+   * Возвращает текст задания.
+   *
+   * @return текст задания
+   */
+  String getText();
+
+  /**
+   * Проверяет ответ на задание и возвращает результат.
+   *
+   * @param answer ответ на задание
+   * @return результат ответа
+   * @see Result
+   */
+  Result validate(String answer);
+}
diff --git a/lab-01/src/by/dudkoandrei/quizer/tasks/TextTask.java b/lab-01/src/by/dudkoandrei/quizer/tasks/TextTask.java
new file mode 100644
index 0000000..e5bc38a
--- /dev/null
+++ b/lab-01/src/by/dudkoandrei/quizer/tasks/TextTask.java
@@ -0,0 +1,52 @@
+package by.dudkoandrei.quizer.tasks;
+
+import by.dudkoandrei.quizer.Result;
+import by.dudkoandrei.quizer.task_generators.PoolTaskGenerator;
+
+/**
+ * Задание с заранее заготовленным текстом. Можно использовать {@link PoolTaskGenerator}, чтобы
+ * задавать задания такого типа.
+ */
+public class TextTask implements Task {
+
+  private final String text;
+  private final String answer;
+
+  /**
+   * @param text   текст задания
+   * @param answer ответ на задание
+   */
+  public TextTask(String text, String answer) {
+    if (text == null || answer == null) {
+      throw new IllegalArgumentException("Arguments shouldn't be null");
+    }
+    if (text.isEmpty() || answer.isEmpty()) {
+      throw new IllegalArgumentException("Arguments shouldn't be empty");
+    }
+
+    this.text = text;
+    this.answer = answer;
+  }
+
+  @Override
+  public String getText() {
+    return text;
+  }
+
+  @Override
+  public Result validate(String answer) {
+    if (answer == null) {
+      throw new IllegalArgumentException("answer is null");
+    }
+
+    if (answer.isEmpty()) {
+      return Result.INCORRECT_INPUT;
+    }
+
+    if (answer.equalsIgnoreCase(this.answer)) {
+      return Result.OK;
+    } else {
+      return Result.WRONG;
+    }
+  }
+}
diff --git a/lab-01/src/by/dudkoandrei/quizer/tasks/math_tasks/AbstractMathTask.java b/lab-01/src/by/dudkoandrei/quizer/tasks/math_tasks/AbstractMathTask.java
new file mode 100644
index 0000000..2c400f8
--- /dev/null
+++ b/lab-01/src/by/dudkoandrei/quizer/tasks/math_tasks/AbstractMathTask.java
@@ -0,0 +1,135 @@
+package by.dudkoandrei.quizer.tasks.math_tasks;
+
+import by.dudkoandrei.quizer.Result;
+import java.text.DecimalFormat;
+import java.util.EnumSet;
+import java.util.Iterator;
+import java.util.Random;
+
+public abstract class AbstractMathTask implements MathTask {
+
+  protected final double answer;
+  protected final double eps;
+  protected String text;
+  protected static final DecimalFormat df = new DecimalFormat();
+
+  AbstractMathTask(double answer, int precision) {
+    if (precision < 0) {
+      throw new IllegalArgumentException("precision is negative");
+    }
+
+    this.answer = answer;
+    this.eps = Math.pow(0.1, precision);
+  }
+
+  static boolean isDoubleEqual(double lhs, double rhs, double eps) {
+    return Math.abs(lhs - rhs) < eps;
+  }
+
+  static double truncate(double number, int precision) {
+    if (precision < 0) {
+      throw new IllegalArgumentException("precision is negative");
+    }
+
+    double scale = Math.pow(10, precision);
+
+    return Math.floor(number * scale) / scale;
+  }
+
+  @Override
+  public Result validate(String answer) {
+    double givenAnswer;
+
+    try {
+      givenAnswer = Double.parseDouble(answer);
+    } catch (NumberFormatException e) {
+      return Result.INCORRECT_INPUT;
+    }
+
+    if (isDoubleEqual(this.answer, givenAnswer, eps)) {
+      return Result.OK;
+    } else {
+      return Result.WRONG;
+    }
+  }
+
+  @Override
+  public String getText() {
+    return text;
+  }
+
+  abstract static class Generator implements MathTask.Generator {
+
+    protected final double minNumber;
+    protected final double maxNumber;
+    protected final int precision;
+    protected final EnumSet<Operation> allowedOperations;
+    protected static final Random rnd = new Random();
+
+    Generator(
+        double minNumber,
+        double maxNumber,
+        EnumSet<Operation> operations) {
+      this(minNumber, maxNumber, 0, operations);
+    }
+
+    Generator(
+        double minNumber,
+        double maxNumber,
+        int precision,
+        EnumSet<Operation> operations) {
+      if (operations == null) {
+        throw new IllegalArgumentException("operations is null");
+      }
+      if (operations.isEmpty()) {
+        throw new IllegalArgumentException("operations is empty");
+      }
+      if (minNumber > maxNumber) {
+        throw new IllegalArgumentException("minNumber is greater that maxNumber");
+      }
+      if (precision < 0) {
+        throw new IllegalArgumentException("precision is negative");
+      }
+
+      this.minNumber = minNumber;
+      this.maxNumber = maxNumber;
+      this.allowedOperations = operations.clone();
+      this.precision = precision;
+    }
+
+    double getRandomDouble() {
+      try {
+        return truncate(rnd.nextDouble(minNumber, maxNumber), precision);
+      } catch (IllegalArgumentException e) {
+        return truncate(minNumber, precision);
+      }
+    }
+
+    Operation getRandomOperation() {
+      int index = rnd.nextInt(allowedOperations.size());
+      Iterator<Operation> iter = allowedOperations.iterator();
+
+      while (index != 0) {
+        iter.next();
+        --index;
+      }
+
+      return iter.next();
+    }
+
+    @Override
+    public double getMinNumber() {
+      return minNumber;
+    }
+
+    @Override
+    public double getMaxNumber() {
+      return maxNumber;
+    }
+
+    @Override
+    public int getPrecision() {
+      return precision;
+    }
+  }
+}
diff --git a/lab-01/src/by/dudkoandrei/quizer/tasks/math_tasks/EquationTask.java b/lab-01/src/by/dudkoandrei/quizer/tasks/math_tasks/EquationTask.java
new file mode 100644
index 0000000..4e61913
--- /dev/null
+++ b/lab-01/src/by/dudkoandrei/quizer/tasks/math_tasks/EquationTask.java
@@ -0,0 +1,92 @@
+package by.dudkoandrei.quizer.tasks.math_tasks;
+
+import java.util.EnumSet;
+
+public class EquationTask extends AbstractMathTask {
+
+  public EquationTask(
+      double firstNumber,
+      double secondNumber,
+      int precision,
+      boolean isFirstNumberUnknown,
+      Operation operation) {
+    super(operation.solve(firstNumber, secondNumber, isFirstNumberUnknown), precision);
+
+    df.setMaximumFractionDigits(precision);
+    df.setMinimumFractionDigits(precision);
+
+    if (isFirstNumberUnknown) {
+      text = "x " + operation + " " + df.format(firstNumber) + " = " + df.format(secondNumber);
+    } else {
+      text = df.format(firstNumber) + " " + operation + " x = " + df.format(secondNumber);
+    }
+  }
+
+  public static class Generator extends AbstractMathTask.Generator {
+
+    /**
+     * @param minNumber  минимальное число
+     * @param maxNumber  максимальное число
+     * @param operations разрешённые операции
+     */
+    public Generator(
+        double minNumber,
+        double maxNumber,
+        EnumSet<Operation> operations) {
+      super(minNumber, maxNumber, operations);
+    }
+
+    /**
+     * @param minNumber  минимальное число
+     * @param maxNumber  максимальное число
+     * @param precision  количество знаков после зяпятой в генерируемых числах
+     * @param operations разрешённые операции
+     */
+    public Generator(
+        double minNumber,
+        double maxNumber,
+        int precision,
+        EnumSet<Operation> operations) {
+      super(minNumber, maxNumber, precision, operations);
+    }
+
+    /**
+     * @return задание типа {@link ExpressionTask}
+     */
+    @Override
+    public EquationTask generate() {
+      double eps = Math.pow(0.1, precision);
+
+      double firstNumber = getRandomDouble();
+      double secondNumber = getRandomDouble();
+      boolean isFirstNumberUnknown = rnd.nextBoolean();
+      Operation operation = getRandomOperation();
+
+      if (operation == Operation.DIVIDE && isDoubleEqual(secondNumber, 0.0, eps)) {
+        operation = Operation.MULTIPLY;
+      }
+      if (operation == Operation.MULTIPLY && isDoubleEqual(firstNumber, 0.0, eps)) {
+        operation = Operation.ADD;
+      }
+      if (isFirstNumberUnknown && operation == Operation.DIVIDE
+          && isDoubleEqual(firstNumber, 0.0, eps)) {
+        operation = Operation.SUBTRACT;
+      }
+      if (!isFirstNumberUnknown && operation == Operation.DIVIDE
+          && isDoubleEqual(secondNumber, 0.0, eps)) {
+        operation = Operation.ADD;
+      }
+      if (precision == 0 && operation == Operation.MULTIPLY
+          && (int) secondNumber % (int) firstNumber != 0) {
+        operation = Operation.SUBTRACT;
+      }
+      if (precision == 0 && !isFirstNumberUnknown && operation == Operation.DIVIDE
+          && (int) firstNumber % (int) secondNumber != 0) {
+        operation = Operation.ADD;
+      }
+
+      return new EquationTask(firstNumber, secondNumber, precision, isFirstNumberUnknown,
+          operation);
+    }
+  }
+}
diff --git a/lab-01/src/by/dudkoandrei/quizer/tasks/math_tasks/ExpressionTask.java b/lab-01/src/by/dudkoandrei/quizer/tasks/math_tasks/ExpressionTask.java
new file mode 100644
index 0000000..641b753
--- /dev/null
+++ b/lab-01/src/by/dudkoandrei/quizer/tasks/math_tasks/ExpressionTask.java
@@ -0,0 +1,69 @@
+package by.dudkoandrei.quizer.tasks.math_tasks;
+
+import java.util.EnumSet;
+
+public class ExpressionTask extends AbstractMathTask {
+
+  public ExpressionTask(
+      double firstNumber,
+      double secondNumber,
+      int precision,
+      Operation operation) {
+    super(operation.compute(firstNumber, secondNumber), precision);
+
+    df.setMaximumFractionDigits(precision);
+    df.setMinimumFractionDigits(precision);
+
+    text = df.format(firstNumber) + " " + operation + " " + df.format(secondNumber) + " = ?";
+  }
+
+  public static class Generator extends AbstractMathTask.Generator {
+
+    /**
+     * @param minNumber  минимальное число
+     * @param maxNumber  максимальное число
+     * @param operations разрешённые операции
+     */
+    public Generator(
+        double minNumber,
+        double maxNumber,
+        EnumSet<Operation> operations) {
+      super(minNumber, maxNumber, operations);
+    }
+
+    /**
+     * @param minNumber  минимальное число
+     * @param maxNumber  максимальное число
+     * @param precision  количество знаков после зяпятой в генерируемых числах
+     * @param operations разрешённые операции
+     */
+    public Generator(
+        double minNumber,
+        double maxNumber,
+        int precision,
+        EnumSet<Operation> operations) {
+      super(minNumber, maxNumber, precision, operations);
+    }
+
+    /**
+     * @return задание типа {@link ExpressionTask}
+     */
+    @Override
+    public ExpressionTask generate() {
+      double firstNumber = getRandomDouble();
+      double secondNumber = getRandomDouble();
+      Operation operation = getRandomOperation();
+
+      if (operation == Operation.DIVIDE
+          && isDoubleEqual(secondNumber, 0.0, Math.pow(0.1, precision))) {
+        operation = Operation.MULTIPLY;
+      }
+      if (precision == 0 && operation == Operation.DIVIDE
+          && (int) firstNumber % (int) secondNumber != 0) {
+        operation = Operation.MULTIPLY;
+      }
+
+      return new ExpressionTask(firstNumber, secondNumber, precision, operation);
+    }
+  }
+}
diff --git a/lab-01/src/by/dudkoandrei/quizer/tasks/math_tasks/MathTask.java b/lab-01/src/by/dudkoandrei/quizer/tasks/math_tasks/MathTask.java
new file mode 100644
index 0000000..72bef9e
--- /dev/null
+++ b/lab-01/src/by/dudkoandrei/quizer/tasks/math_tasks/MathTask.java
@@ -0,0 +1,71 @@
+package by.dudkoandrei.quizer.tasks.math_tasks;
+
+import by.dudkoandrei.quizer.tasks.Task;
+
+public interface MathTask extends Task {
+
+  interface Generator extends Task.Generator {
+
+    /**
+     * @return минимальное число
+     */
+    double getMinNumber();
+
+    /**
+     * @return максимальное число
+     */
+    double getMaxNumber();
+
+    /**
+     * @return количество знаков после запятой в генерируемых числах
+     */
+    int getPrecision();
+
+    /**
+     * @return разница между максимальным и минимальным возможным числом
+     */
+    default double getDiffNumber() {
+      return getMaxNumber() - getMinNumber();
+    }
+  }
+
+  /**
+   * Enum, который описывает допустимые операции для {@link MathTask}.
+   */
+  enum Operation {
+    ADD,
+    SUBTRACT,
+    DIVIDE,
+    MULTIPLY;
+
+    double compute(double lhs, double rhs) {
+      return switch (this) {
+        case ADD -> lhs + rhs;
+        case SUBTRACT -> lhs - rhs;
+        case MULTIPLY -> lhs * rhs;
+        case DIVIDE -> lhs / rhs;
+      };
+    }
+
+    @Override
+    public String toString() {
+      return switch (this) {
+        case ADD -> "+";
+        case SUBTRACT -> "-";
+        case MULTIPLY -> "*";
+        case DIVIDE -> "/";
+      };
+    }
+
+    double solve(double firstNumber, double secondNumber, boolean isFirstNumberUnknown) {
+      return switch (this) {
+        case ADD -> secondNumber - firstNumber;
+        case MULTIPLY -> secondNumber / firstNumber;
+        case SUBTRACT ->
+            isFirstNumberUnknown ? secondNumber + firstNumber : firstNumber - secondNumber;
+        case DIVIDE ->
+            isFirstNumberUnknown ? firstNumber * secondNumber : firstNumber / secondNumber;
+      };
+    }
+  }
+}