Adding Math Fibonacci

src/main/java/FibonacciSeries/abstractions/IFibonacciCalculator.java

 package FibonacciSeries.abstractions;
 
 public interface IFibonacciCalculator {
-    long calculate(long number);
+    double calculate(long number);
 }

src/main/java/FibonacciSeries/implementation/MathFibonacciCalculator.java

+package FibonacciSeries.implementation;
+
+import FibonacciSeries.abstractions.IFibonacciCalculator;
+
+public class MathFibonacciCalculator implements IFibonacciCalculator {
+    @Override
+    public double calculate(long number) {
+        double item1 = (1 + Math.sqrt(5))/2;
+        double item2 = (1 - Math.sqrt(5))/2;
+        item1 = Math.pow(item1,number);
+        item2 = Math.pow(item2,number);
+        return Math.round((item1 + item2)/Math.sqrt(5));
+    }
+}

src/main/java/FibonacciSeries/implementation/NormalFibonacciCalculator.java

@@ -4,7 +4,7 @@ import FibonacciSeries.abstractions.IFibonacciCalculator;
 
 public class NormalFibonacciCalculator implements IFibonacciCalculator {
     @Override
-    public long calculate(long number) {
+    public double calculate(long number) {
         long firstItem = 0;
         long secondItem = 1;
 

src/main/java/FibonacciSeries/implementation/ParallelFibonacciCalculator.java

@@ -4,7 +4,7 @@ import FibonacciSeries.abstractions.IFibonacciCalculator;
 
 public class ParallelFibonacciCalculator implements IFibonacciCalculator {
     @Override
-    public long calculate(long number) {
+    public double calculate(long number) {
         return 0;
     }
 }

src/main/java/FibonacciSeries/runners/Main.java

 package FibonacciSeries.runners;
 
 import FibonacciSeries.abstractions.IFibonacciCalculator;
+import FibonacciSeries.implementation.MathFibonacciCalculator;
 import FibonacciSeries.implementation.NormalFibonacciCalculator;
 
 public class Main {
     public static void main(String[] args) {
-        IFibonacciCalculator calculator = new NormalFibonacciCalculator();
+        IFibonacciCalculator calculator = new MathFibonacciCalculator();
         for (int i = 0; i < 10; i++) {
             System.out.println("F("+i+") = "+calculator.calculate(i));
         }