diff --git a/src/main/java/core/basesyntax/Calculator.java b/src/main/java/core/basesyntax/Calculator.java
new file mode 100644
index 00000000..c531f8f3
--- /dev/null
+++ b/src/main/java/core/basesyntax/Calculator.java
@@ -0,0 +1,5 @@
+package core.basesyntax;
+
+public interface Calculator {
+    double calculate(double firstValue, double secondValue, char operation);
+}
diff --git a/src/main/java/core/basesyntax/HelloWorld.java b/src/main/java/core/basesyntax/HelloWorld.java
deleted file mode 100644
index 97db782b..00000000
--- a/src/main/java/core/basesyntax/HelloWorld.java
+++ /dev/null
@@ -1,8 +0,0 @@
-package core.basesyntax;
-
-/**
- * Feel free to remove this class and create your own.
- */
-public class HelloWorld {
-
-}
diff --git a/src/main/java/core/basesyntax/MyCalculator.java b/src/main/java/core/basesyntax/MyCalculator.java
new file mode 100644
index 00000000..63689cd8
--- /dev/null
+++ b/src/main/java/core/basesyntax/MyCalculator.java
@@ -0,0 +1,30 @@
+package core.basesyntax;
+
+public class MyCalculator implements Calculator {
+    public static final char ADDITION = '+';
+    public static final char SUBTRACTION = '-';
+    public static final char DIVISION = '/';
+    public static final char MULTIPLICATION = '*';
+    public static final char RISING_TO_POWER = '^';
+
+    @Override
+    public double calculate(double firstValue, double secondValue, char operation) {
+        switch (operation) {
+            case ADDITION :
+                return firstValue + secondValue;
+            case SUBTRACTION :
+                return firstValue - secondValue;
+            case DIVISION :
+                if (secondValue == 0) {
+                    throw new ArithmeticException("Second value can't be 0!");
+                }
+                return firstValue / secondValue;
+            case MULTIPLICATION :
+                return firstValue * secondValue;
+            case RISING_TO_POWER :
+                return Math.pow(firstValue, secondValue);
+            default:
+                throw new UnknownOperationException("Unknown operation");
+        }
+    }
+}
diff --git a/src/main/java/core/basesyntax/UnknownOperationException.java b/src/main/java/core/basesyntax/UnknownOperationException.java
new file mode 100644
index 00000000..2214fbac
--- /dev/null
+++ b/src/main/java/core/basesyntax/UnknownOperationException.java
@@ -0,0 +1,7 @@
+package core.basesyntax;
+
+public class UnknownOperationException extends RuntimeException {
+    public UnknownOperationException(String message) {
+        super(message);
+    }
+}
diff --git a/src/test/java/core/basesyntax/HelloWorldTest.java b/src/test/java/core/basesyntax/HelloWorldTest.java
deleted file mode 100644
index 9a90d822..00000000
--- a/src/test/java/core/basesyntax/HelloWorldTest.java
+++ /dev/null
@@ -1,8 +0,0 @@
-package core.basesyntax;
-
-/**
- * Feel free to remove this class and create your own.
- */
-public class HelloWorldTest {
-
-}
diff --git a/src/test/java/core/basesyntax/MyCalculatorTest.java b/src/test/java/core/basesyntax/MyCalculatorTest.java
new file mode 100644
index 00000000..b83740da
--- /dev/null
+++ b/src/test/java/core/basesyntax/MyCalculatorTest.java
@@ -0,0 +1,267 @@
+package core.basesyntax;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+class MyCalculatorTest {
+    public static final char ADDITION = '+';
+    public static final char SUBTRACTION = '-';
+    public static final char DIVISION = '/';
+    public static final char MULTIPLICATION = '*';
+    public static final char RISING = '^';
+    private static final double DELTA = 0.00001;
+    private static Calculator calculator;
+
+    @BeforeAll
+    static void beforeAll() {
+        calculator = new MyCalculator();
+    }
+
+    @Test
+    void calculate_additionTwoPositiveOperands_OK() {
+        double actual = calculator.calculate(10, 5, ADDITION);
+        double expected = 15;
+        assertEquals(expected,actual);
+    }
+
+    @Test
+    void calculate_additionTwoNegativeOperands_OK() {
+        double actual = calculator.calculate(-10, -5, ADDITION);
+        double expected = -15;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_additionNegativeAndPositiveOperands_OK() {
+        double actual = calculator.calculate(-10,5, ADDITION);
+        double expected = -5;
+        assertEquals(expected,actual);
+    }
+
+    @Test
+    void calculate_additionWithZero_OK() {
+        double actual = calculator.calculate(0, 10, ADDITION);
+        double expected = 10;
+        assertEquals(expected, actual);
+        actual = calculator.calculate(10, 0, ADDITION);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_additionWithMaxValues_OK() {
+        double actual = calculator.calculate(Double.MAX_VALUE, Double.MAX_VALUE, ADDITION);
+        double expected = Double.POSITIVE_INFINITY;
+        assertEquals(expected, actual, DELTA);
+    }
+
+    @Test
+    void calculate_additionWithMinValue_OK() {
+        double actual = calculator.calculate(Double.MIN_VALUE, Double.MIN_VALUE, ADDITION);
+        double expected = 0;
+        assertEquals(expected,actual,DELTA);
+    }
+
+    @Test
+    void calculate_subtractionWithTwoPositiveOperands_OK() {
+        double actual = calculator.calculate(10, 5, SUBTRACTION);
+        double expected = 5;
+        assertEquals(expected,actual);
+    }
+
+    @Test
+    void calculate_subtractionWithTwoNegativeOperands_OK() {
+        double actual = calculator.calculate(-10, -5, SUBTRACTION);
+        double expected = -5;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_subtractionWithNegativeAndPositiveOperands_OK() {
+        double actual = calculator.calculate(-5, 10, SUBTRACTION);
+        double expected = -15;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_subtractionWithZeroOperands_OK() {
+        double actual = calculator.calculate(10, 0, SUBTRACTION);
+        double expected = 10;
+        assertEquals(expected, actual);
+        expected = -10;
+        actual = calculator.calculate(0, 10, SUBTRACTION);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_subtractionWithMaxValues_OK() {
+        double actual = calculator.calculate(Double.MAX_VALUE, Double.MAX_VALUE, SUBTRACTION);
+        double expected = 0;
+        assertEquals(expected, actual, DELTA);
+    }
+
+    @Test
+    void calculate_subtractionWithMinValues_OK() {
+        double actual = calculator.calculate(Double.MIN_VALUE, Double.MIN_VALUE, SUBTRACTION);
+        double expected = 0;
+        assertEquals(expected, actual, DELTA);
+    }
+
+    @Test
+    void calculate_divisionWithTwoPositiveOperands_OK() {
+        double actual = calculator.calculate(10, 5, DIVISION);
+        double expected = 2;
+        assertEquals(expected,actual);
+    }
+
+    @Test
+    void calculate_divisionWithTwoNegativeOperands_OK() {
+        double actual = calculator.calculate(-10, -5, DIVISION);
+        double expected = 2;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_divisionWithNegativeAndPositiveOperands_OK() {
+        double actual = calculator.calculate(-10, 2, DIVISION);
+        double expected = -5;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_divisionWithFirstZeroOperands_OK() {
+        double actual = calculator.calculate(0, 10, DIVISION);
+        double expected = 0;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_divisionOnZero_NotOK() {
+        assertThrows(ArithmeticException.class, () -> {
+            calculator.calculate(10, 0, DIVISION);
+        });
+    }
+
+    @Test
+    void calculate_divisionWithMaxValues_OK() {
+        double actual = calculator.calculate(Double.MAX_VALUE, Double.MAX_VALUE, DIVISION);
+        double expected = 1;
+        assertEquals(expected, actual, DELTA);
+    }
+
+    @Test
+    void calculate_divisionWithMinValues_OK() {
+        double actual = calculator.calculate(Double.MIN_VALUE, Double.MIN_VALUE, DIVISION);
+        double expected = 1;
+        assertEquals(expected, actual, DELTA);
+    }
+
+    @Test
+    void calculate_multiplicationTwoPositiveOperands_OK() {
+        double actual = calculator.calculate(10, 5, MULTIPLICATION);
+        double expected = 50;
+        assertEquals(expected,actual);
+    }
+
+    @Test
+    void calculate_multiplicationTwoNegativeOperands_OK() {
+        double actual = calculator.calculate(-10, -5, MULTIPLICATION);
+        double expected = 50;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_multiplicationNegativeAndPositiveOperands_OK() {
+        double actual = calculator.calculate(-10,5, MULTIPLICATION);
+        double expected = -50;
+        assertEquals(expected,actual);
+    }
+
+    @Test
+    void calculate_multiplicationWithZero_OK() {
+        double actual = calculator.calculate(0, 10, MULTIPLICATION);
+        double expected = 0;
+        assertEquals(expected, actual);
+        actual = calculator.calculate(10, 0, MULTIPLICATION);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_multiplicationWithMaxValues_OK() {
+        double actual = calculator.calculate(Double.MAX_VALUE, Double.MAX_VALUE, MULTIPLICATION);
+        double expected = Double.POSITIVE_INFINITY;
+        assertEquals(expected, actual, DELTA);
+    }
+
+    @Test
+    void calculate_multiplicationWithMinValue_OK() {
+        double actual = calculator.calculate(Double.MIN_VALUE, Double.MIN_VALUE, MULTIPLICATION);
+        double expected = 0;
+        assertEquals(expected,actual,DELTA);
+    }
+
+    @Test
+    void calculate_raisingPositiveToPositivePower_OK() {
+        double expected = 32;
+        double actual = calculator.calculate(2, 5, RISING);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_raisingPositiveToNegativePower_OK() {
+        double expected = 0.125;
+        double actual = calculator.calculate(2, -3, RISING);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_raisingNegativeToNegativePower_OK() {
+        double expected = -0.125;
+        double actual = calculator.calculate(-2, -3, RISING);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_raisingNegativeToPositivePower_OK() {
+        double expected = -27;
+        double actual = calculator.calculate(-3, 3, RISING);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_raisingPositiveValueToZeroPower_OK() {
+        double expected = 1;
+        double actual = calculator.calculate(5, 0, RISING);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_raisingNegativeValueToZeroPower_OK() {
+        double expected = 1;
+        double actual = calculator.calculate(-5, 0, RISING);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_raisingZeroToPower_OK() {
+        double expected = 0;
+        double actual = calculator.calculate(0, 5, RISING);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_zeroToNegativePower_OK() {
+        double expected = Double.POSITIVE_INFINITY;
+        double actual = calculator.calculate(0, -3, RISING);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_unknownOperation_OK() {
+        assertThrows(UnknownOperationException.class, () -> {
+            calculator.calculate(10, 10, '.');
+        });
+    }
+}