diff --git a/src/main/java/core/basesyntax/Calculator.java b/src/main/java/core/basesyntax/Calculator.java
new file mode 100644
index 00000000..5a23d041
--- /dev/null
+++ b/src/main/java/core/basesyntax/Calculator.java
@@ -0,0 +1,19 @@
+package core.basesyntax;
+
+public class Calculator {
+
+    public double calculate(double x, double y, char operation) {
+        double result;
+        switch (operation) {
+            case '+': return x + y;
+            case '-': return x - y;
+            case '*': return (result = x * y) == -0.0 ? 0 : result;
+            case '/': if (y == 0) {
+                    throw new IllegalArgumentException("Division by zero!");
+                }
+                return (result = x / y) == -0.0 ? 0 : result;
+            case '^': return Math.pow(x, y);
+            default: throw new UnsupportedOperationException("Illegal 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/test/java/core/basesyntax/CalculatorTest.java b/src/test/java/core/basesyntax/CalculatorTest.java
new file mode 100644
index 00000000..c0ae9937
--- /dev/null
+++ b/src/test/java/core/basesyntax/CalculatorTest.java
@@ -0,0 +1,347 @@
+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_VALUE = 0.00001;
+
+    @BeforeAll
+    static void beforeAll() {
+        calculator = new Calculator();
+    }
+
+    @Test
+    void calculate_addPositiveValues_Ok() {
+        double actual = calculator.calculate(100, 200, '+');
+        double expected = 300;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_addNegativeValues_Ok() {
+        double actual = calculator.calculate(-100, -200, '+');
+        double expected = -300;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_addPositiveAndNegative_Ok() {
+        double actual = calculator.calculate(-100, 200, '+');
+        double expected = 100;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_addZero_Ok() {
+        double actual = calculator.calculate(0, -200, '+');
+        double expected = -200;
+        assertEquals(expected, actual);
+        actual = calculator.calculate(100, 0, '+');
+        expected = 100;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_addMaxValues_Ok() {
+        double actual = calculator.calculate(Double.MAX_VALUE, Double.MAX_VALUE, '+');
+        double expected = Double.POSITIVE_INFINITY;
+        assertEquals(expected, actual);
+        actual = calculator.calculate(Double.MAX_VALUE, -Double.MAX_VALUE, '+');
+        expected = 0;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_addMaxAndMinValues_Ok() {
+        double actual = calculator.calculate(Double.MAX_VALUE, Double.MIN_VALUE, '+');
+        double expected = Double.MAX_VALUE;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_addMinValues_Ok() {
+        double actual = calculator.calculate(Double.MIN_VALUE, Double.MIN_VALUE, '+');
+        double expected = 1.0E-323;
+        assertEquals(expected, actual);
+        actual = calculator.calculate(Double.MIN_VALUE, -Double.MIN_VALUE, '+');
+        expected = 0;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_subPositiveValues_Ok() {
+        double actual = calculator.calculate(100, 200, '-');
+        double expected = -100;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_subNegativeValues_Ok() {
+        double actual = calculator.calculate(-100, -200, '-');
+        double expected = 100;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_subPositiveAndNegative_Ok() {
+        double actual = calculator.calculate(-100, 200, '-');
+        double expected = -300;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_subZero_Ok() {
+        double actual = calculator.calculate(0, -200, '-');
+        double expected = 200;
+        assertEquals(expected, actual);
+        actual = calculator.calculate(100, 0, '-');
+        expected = 100;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_subMaxValues_Ok() {
+        double actual = calculator.calculate(Double.MAX_VALUE, Double.MAX_VALUE, '-');
+        double expected = 0;
+        assertEquals(expected, actual);
+        actual = calculator.calculate(Double.MAX_VALUE, -Double.MAX_VALUE, '-');
+        expected = Double.POSITIVE_INFINITY;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_subMaxAndMinValues_Ok() {
+        double actual = calculator.calculate(Double.MAX_VALUE, Double.MIN_VALUE, '-');
+        double expected = Double.MAX_VALUE;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_subMinValues_Ok() {
+        double actual = calculator.calculate(Double.MIN_VALUE, Double.MIN_VALUE, '-');
+        double expected = 0;
+        assertEquals(expected, actual);
+        actual = calculator.calculate(Double.MIN_VALUE, -Double.MIN_VALUE, '-');
+        expected = 1.0E-323;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_mulPositiveValues_Ok() {
+        double actual = calculator.calculate(100, 200, '*');
+        double expected = 20000;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_mulNegativeValues_Ok() {
+        double actual = calculator.calculate(-100, -200, '*');
+        double expected = 20000;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_mulPositiveAndNegative_Ok() {
+        double actual = calculator.calculate(-100, 200, '*');
+        double expected = -20000;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_mulZero_Ok() {
+        double actual = calculator.calculate(0, -200, '*');
+        double expected = 0.0;
+        assertEquals(expected, actual);
+        actual = calculator.calculate(100, 0, '*');
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_mulMaxValues_Ok() {
+        double actual = calculator.calculate(Double.MAX_VALUE, Double.MAX_VALUE, '*');
+        double expected = Double.POSITIVE_INFINITY;
+        assertEquals(expected, actual);
+        actual = calculator.calculate(Double.MAX_VALUE, -Double.MAX_VALUE, '*');
+        expected = Double.NEGATIVE_INFINITY;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_mulMaxAndMinValues_Ok() {
+        double actual = calculator.calculate(Double.MAX_VALUE, Double.MIN_VALUE, '*');
+        double expected = 8.881784197001251E-16;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_mulMinValues_Ok() {
+        double actual = calculator.calculate(Double.MIN_VALUE, Double.MIN_VALUE, '*');
+        double expected = 0;
+        assertEquals(expected, actual);
+        actual = calculator.calculate(Double.MIN_VALUE, -Double.MIN_VALUE, '*');
+        expected = 0;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_divPositiveValues_Ok() {
+        double actual = calculator.calculate(125, 200, '/');
+        double expected = 0.625;
+        assertEquals(expected, actual, DELTA_VALUE);
+    }
+
+    @Test
+    void calculate_divNegativeValues_Ok() {
+        double actual = calculator.calculate(-401, -200, '/');
+        double expected = 2.005;
+        assertEquals(expected, actual, DELTA_VALUE);
+    }
+
+    @Test
+    void calculate_divPositiveAndNegative_Ok() {
+        double actual = calculator.calculate(-179, 200, '/');
+        double expected = -0.895;
+        assertEquals(expected, actual, DELTA_VALUE);
+    }
+
+    @Test
+    void calculate_divZero_Ok() {
+        double actual = calculator.calculate(0, -200, '/');
+        double expected = 0.0;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_divByZero_NotOk() {
+        assertThrows(IllegalArgumentException.class, () -> calculator.calculate(100, 0, '/'));
+    }
+
+    @Test
+    void calculate_divMaxValues_Ok() {
+        double actual = calculator.calculate(Double.MAX_VALUE, Double.MAX_VALUE, '/');
+        double expected = 1;
+        assertEquals(expected, actual);
+        actual = calculator.calculate(Double.MAX_VALUE, -Double.MAX_VALUE, '/');
+        expected = -1;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_divMaxAndMinValues_Ok() {
+        double actual = calculator.calculate(Double.MAX_VALUE, Double.MIN_VALUE, '/');
+        double expected = Double.POSITIVE_INFINITY;
+        assertEquals(expected, actual);
+        actual = calculator.calculate(Double.MIN_VALUE, Double.MAX_VALUE, '/');
+        expected = Double.MIN_VALUE;
+        assertEquals(expected, actual, Double.MIN_VALUE);
+    }
+
+    @Test
+    void calculate_divMinValues_Ok() {
+        double actual = calculator.calculate(Double.MIN_VALUE, Double.MIN_VALUE, '/');
+        double expected = 1;
+        assertEquals(expected, actual);
+        actual = calculator.calculate(Double.MIN_VALUE, -Double.MIN_VALUE, '/');
+        expected = -1;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_raisingToPositivePower_Ok() {
+        double actual = calculator.calculate(5, 4, '^');
+        double expected = 625;
+        assertEquals(expected, actual);
+        actual = calculator.calculate(-5, 5, '^');
+        expected = -3125;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_raisingToNegativePower_Ok() {
+        double actual = calculator.calculate(5, -4, '^');
+        double expected = 0.0016;
+        assertEquals(expected, actual, DELTA_VALUE);
+        actual = calculator.calculate(-5, -5, '^');
+        expected = -0.00032;
+        assertEquals(expected, actual, DELTA_VALUE);
+    }
+
+    @Test
+    void calculate_raisingToZeroPower_Ok() {
+        double actual = calculator.calculate(5, 0, '^');
+        double expected = 1;
+        assertEquals(expected, actual);
+        actual = calculator.calculate(-5, 0, '^');
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_raisingZeroToPower_Ok() {
+        double actual = calculator.calculate(0, 5, '^');
+        double expected = 0;
+        assertEquals(expected, actual);
+        actual = calculator.calculate(0, -5, '^');
+        expected = Double.POSITIVE_INFINITY;
+        assertEquals(expected, actual);
+        actual = calculator.calculate(0, 0, '^');
+        expected = 1;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_raisingMaxValuesToPower_Ok() {
+        double actual = calculator.calculate(Double.MAX_VALUE, Double.MAX_VALUE, '^');
+        double expected = Double.POSITIVE_INFINITY;
+        assertEquals(expected, actual);
+        actual = calculator.calculate(-Double.MAX_VALUE, Double.MAX_VALUE, '^');
+        assertEquals(expected, actual);
+        actual = calculator.calculate(Double.MAX_VALUE, -Double.MAX_VALUE, '^');
+        expected = 0;
+        assertEquals(expected, actual);
+        actual = calculator.calculate(-Double.MAX_VALUE, -Double.MAX_VALUE, '^');
+        expected = 0;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_raisingMinValuesToPower_Ok() {
+        double actual = calculator.calculate(Double.MIN_VALUE, Double.MIN_VALUE, '^');
+        double expected = 1;
+        assertEquals(expected, actual);
+        expected = Double.NaN;
+        actual = calculator.calculate(-Double.MIN_VALUE, Double.MIN_VALUE, '^');
+        assertEquals(expected, actual);
+        actual = calculator.calculate(Double.MIN_VALUE, -Double.MIN_VALUE, '^');
+        expected = 1;
+        assertEquals(expected, actual);
+        actual = calculator.calculate(-Double.MIN_VALUE, -Double.MIN_VALUE, '^');
+        expected = Double.NaN;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_raisingMinAndMaxValuesToPower_Ok() {
+        double actual = calculator.calculate(Double.MAX_VALUE, Double.MIN_VALUE, '^');
+        double expected = 1;
+        assertEquals(expected, actual);
+        actual = calculator.calculate(Double.MAX_VALUE, -Double.MIN_VALUE, '^');
+        assertEquals(expected, actual);
+        expected = 0;
+        actual = calculator.calculate(Double.MIN_VALUE, Double.MAX_VALUE, '^');
+        assertEquals(expected, actual);
+        actual = calculator.calculate(Double.MIN_VALUE, -Double.MAX_VALUE, '^');
+        expected = Double.POSITIVE_INFINITY;
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_illegalOperation_NotOk() {
+        assertThrows(UnsupportedOperationException.class, () -> calculator.calculate(1, 1, '!'));
+    }
+
+}
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 {
-
-}