diff --git a/src/main/java/core/basesyntax/Calculator.java b/src/main/java/core/basesyntax/Calculator.java
new file mode 100644
index 00000000..c0480d4c
--- /dev/null
+++ b/src/main/java/core/basesyntax/Calculator.java
@@ -0,0 +1,27 @@
+package core.basesyntax;
+
+public class Calculator {
+
+    public double calculate(double firstValue, double secondValue, char operation) {
+        switch (operation) {
+            case '+':
+                return firstValue + secondValue;
+            case '-':
+                return firstValue - secondValue;
+            case '/':
+                if (secondValue == 0) {
+                    throw new RuntimeException("Error, division by 0");
+                }
+                return firstValue / secondValue;
+            case '*':
+                return firstValue * secondValue;
+            case '^':
+                if (firstValue < 0 && secondValue != (long) secondValue) {
+                    throw new RuntimeException("Error");
+                }
+                return Math.pow(firstValue, secondValue);
+            default:
+                throw new RuntimeException("Error, unknown operation type");
+        }
+    }
+}
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/test/java/core/basesyntax/CalculatorTest.java b/src/test/java/core/basesyntax/CalculatorTest.java
new file mode 100644
index 00000000..dc47302f
--- /dev/null
+++ b/src/test/java/core/basesyntax/CalculatorTest.java
@@ -0,0 +1,236 @@
+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;
+
+public class CalculatorTest {
+    private static Calculator calculator;
+    private static final double DELTA = 0.0001;
+    private static final double POSITIVE_NUMBER_1 = 23.4;
+    private static final double POSITIVE_NUMBER_2 = 700.5;
+    private static final double POSITIVE_NUMBER_3 = 321.45;
+    private static final double POSITIVE_NUMBER_4 = 8;
+    private static final double POSITIVE_NUMBER_5 = 25;
+    private static final double POSITIVE_NUMBER_6 = 2.5;
+    private static final double POSITIVE_NUMBER_7 = 4.5;
+    private static final double NEGATIVE_NUMBER_1 = -23.4;
+    private static final double NEGATIVE_NUMBER_2 = -700.5;
+    private static final double NEGATIVE_NUMBER_3 = -8;
+    private static final double NEGATIVE_NUMBER_4 = -25;
+    private static final double NEGATIVE_NUMBER_5 = -2.5;
+    private static final double ZERO_NUMBER = 0;
+    private double actual;
+    private double expected;
+
+    @BeforeAll
+    static void beforeAll() {
+        calculator = new Calculator();
+    }
+
+    @Test
+    void calculate_additionWithTwoPositiveOperands_isOk() {
+        actual = calculator.calculate(POSITIVE_NUMBER_1, POSITIVE_NUMBER_2, '+');
+        expected = 723.9;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_additionWithTwoNegativeOperands_isOk() {
+        expected = -723.9;
+        actual = calculator.calculate(NEGATIVE_NUMBER_1, NEGATIVE_NUMBER_2, '+');
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_additionWithPositiveAndNegativeOperands_isOk() {
+        expected = 677.1;
+        actual = calculator.calculate(NEGATIVE_NUMBER_1, POSITIVE_NUMBER_2, '+');
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_additionWithZeroInDifferentPlaces_isOk() {
+        expected = POSITIVE_NUMBER_2;
+        actual = calculator.calculate(ZERO_NUMBER, POSITIVE_NUMBER_2, '+');
+        assertEquals(expected, actual);
+        expected = POSITIVE_NUMBER_3;
+        actual = calculator.calculate(POSITIVE_NUMBER_3, ZERO_NUMBER, '+');
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_additionForMinAndMaxDoubleValues_isOk() {
+        expected = Double.MAX_VALUE;
+        actual = calculator.calculate(Double.MAX_VALUE, Double.MIN_VALUE, '+');
+        assertEquals(expected, actual, DELTA);
+    }
+
+    @Test
+    void calculate_subtractionWithTwoPositiveOperands_isOk() {
+        actual = calculator.calculate(POSITIVE_NUMBER_1, POSITIVE_NUMBER_2, '-');
+        expected = -677.1;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_subtractionWithTwoNegativeOperands_isOk() {
+        expected = 677.1;
+        actual = calculator.calculate(NEGATIVE_NUMBER_1, NEGATIVE_NUMBER_2, '-');
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_subtractionWithPositiveAndNegativeOperands_isOk() {
+        expected = -723.9;
+        actual = calculator.calculate(NEGATIVE_NUMBER_1, POSITIVE_NUMBER_2, '-');
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_subtractionWithZeroInDifferentPlaces_isOk() {
+        expected = NEGATIVE_NUMBER_2;
+        actual = calculator.calculate(ZERO_NUMBER, POSITIVE_NUMBER_2, '-');
+        assertEquals(expected, actual);
+        expected = POSITIVE_NUMBER_3;
+        actual = calculator.calculate(POSITIVE_NUMBER_3, ZERO_NUMBER, '-');
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_subtractionForMinAndMaxDoubleValues_isOk() {
+        actual = calculator.calculate(Double.MAX_VALUE, Double.MIN_VALUE, '-');
+        expected = Double.MAX_VALUE;
+        assertEquals(expected, actual, DELTA);
+    }
+
+    @Test
+    void calculate_multiplicationWithTwoPositiveOperands_isOk() {
+        actual = calculator.calculate(POSITIVE_NUMBER_1, POSITIVE_NUMBER_2, '*');
+        expected = 16391.7;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_multiplicationWithTwoNegativeOperands_isOk() {
+        expected = 16391.7;
+        actual = calculator.calculate(NEGATIVE_NUMBER_1, NEGATIVE_NUMBER_2, '*');
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_multiplicationWithPositiveAndNegativeOperands_isOk() {
+        expected = -16391.7;
+        actual = calculator.calculate(NEGATIVE_NUMBER_1, POSITIVE_NUMBER_2, '*');
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_multiplicationWithZeroInDifferentPlaces_isOk() {
+        expected = ZERO_NUMBER;
+        actual = calculator.calculate(ZERO_NUMBER, POSITIVE_NUMBER_2, '*');
+        assertEquals(expected, actual);
+        actual = calculator.calculate(POSITIVE_NUMBER_3, ZERO_NUMBER, '*');
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_multiplicationForMinAndMaxDoubleValues_isOk() {
+        expected = ZERO_NUMBER;
+        actual = calculator.calculate(Double.MAX_VALUE, Double.MIN_VALUE, '*');
+        assertEquals(expected, actual, DELTA);
+    }
+
+    @Test
+    void calculate_divisionWithTwoPositiveOperands_isOk() {
+        expected = 0.32;
+        actual = calculator.calculate(POSITIVE_NUMBER_4, POSITIVE_NUMBER_5, '/');
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_divisionWithTwoNegativeOperands_isOk() {
+        expected = 0.32;
+        actual = calculator.calculate(NEGATIVE_NUMBER_3, NEGATIVE_NUMBER_4, '/');
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_divisionWithPositiveAndNegativeOperands_isOk() {
+        expected = -0.32;
+        actual = calculator.calculate(POSITIVE_NUMBER_4, NEGATIVE_NUMBER_4, '/');
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_divisionWithZeroInDifferentPlaces() {
+        expected = ZERO_NUMBER;
+        actual = calculator.calculate(ZERO_NUMBER, POSITIVE_NUMBER_5, '/');
+        assertEquals(expected, actual);
+        assertThrows(RuntimeException.class,
+                () -> calculator.calculate(POSITIVE_NUMBER_4, ZERO_NUMBER, '/'));
+    }
+
+    @Test
+    void calculate_raisingForMinAndMaxDoubleValues() {
+        expected = 1;
+        actual = calculator.calculate(Double.MAX_VALUE, Double.MIN_VALUE, '^');
+        assertEquals(expected, actual, DELTA);
+        actual = calculator.calculate(Double.MAX_VALUE, Double.MIN_VALUE, '^');
+        assertEquals(expected, actual, DELTA);
+    }
+
+    @Test
+    void calculate_raisingPositiveOrNegativeValueToThePositivePower() {
+        expected = 61.763235;
+        actual = calculator.calculate(POSITIVE_NUMBER_6, POSITIVE_NUMBER_7, '^');
+        assertEquals(expected, actual, DELTA);
+        assertThrows(RuntimeException.class,
+                () -> calculator.calculate(NEGATIVE_NUMBER_5, POSITIVE_NUMBER_7, '^'));
+
+    }
+
+    @Test
+    void calculate_raisingPositiveOrNegativeValueToTheNegativePower() {
+        expected = 0.02327;
+        actual = calculator.calculate(POSITIVE_NUMBER_7, NEGATIVE_NUMBER_5, '^');
+        assertEquals(expected, actual, DELTA);
+        assertThrows(RuntimeException.class,
+                () -> calculator.calculate(NEGATIVE_NUMBER_5, NEGATIVE_NUMBER_5, '^'));
+    }
+
+    @Test
+    void calculate_raisingPositiveOrNegativeValueToTheZeroPower() {
+        expected = 1;
+        actual = calculator.calculate(POSITIVE_NUMBER_7, ZERO_NUMBER, '^');
+        assertEquals(expected, actual);
+        actual = calculator.calculate(NEGATIVE_NUMBER_5, ZERO_NUMBER, '^');
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_raisingZeroToPower() {
+        expected = ZERO_NUMBER;
+        actual = calculator.calculate(ZERO_NUMBER, POSITIVE_NUMBER_7, '^');
+        assertEquals(expected, actual);
+        expected = Double.POSITIVE_INFINITY;
+        actual = calculator.calculate(ZERO_NUMBER, NEGATIVE_NUMBER_5, '^');
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_illegalOperations_ExceptionOk() {
+        assertThrows(RuntimeException.class,
+                () -> calculator.calculate(ZERO_NUMBER, ZERO_NUMBER, '='));
+        assertThrows(RuntimeException.class,
+                () -> calculator.calculate(ZERO_NUMBER, ZERO_NUMBER, '!'));
+        assertThrows(RuntimeException.class,
+                () -> calculator.calculate(ZERO_NUMBER, ZERO_NUMBER, '$'));
+        assertThrows(RuntimeException.class,
+                () -> calculator.calculate(ZERO_NUMBER, ZERO_NUMBER, '%'));
+        assertThrows(RuntimeException.class,
+                () -> calculator.calculate(ZERO_NUMBER, ZERO_NUMBER, '('));
+    }
+}
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 {
-
-}