diff --git a/src/main/java/htw/berlin/prog2/ha1/Calculator.java b/src/main/java/htw/berlin/prog2/ha1/Calculator.java
index 84c04f2..bf5b247 100644
--- a/src/main/java/htw/berlin/prog2/ha1/Calculator.java
+++ b/src/main/java/htw/berlin/prog2/ha1/Calculator.java
@@ -45,9 +45,11 @@ public void pressDigitKey(int digit) {
      * im Ursprungszustand ist.
      */
     public void pressClearKey() {
+        if (screen.equals("0")) {
+            latestValue = 0.0;
+            latestOperation = "";
+        }
         screen = "0";
-        latestOperation = "";
-        latestValue = 0.0;
     }
 
     /**
@@ -83,7 +85,7 @@ public void pressUnaryOperationKey(String operation) {
         screen = Double.toString(result);
         if(screen.equals("NaN")) screen = "Error";
         if(screen.contains(".") && screen.length() > 11) screen = screen.substring(0, 10);
-
+        if(screen.endsWith(".0")) screen = screen.substring(0, screen.length() - 2);
     }
 
     /**
diff --git a/src/main/java/htw/berlin/prog2/ha1/Vector.java b/src/main/java/htw/berlin/prog2/ha1/Vector.java
new file mode 100644
index 0000000..c9bb8d4
--- /dev/null
+++ b/src/main/java/htw/berlin/prog2/ha1/Vector.java
@@ -0,0 +1,26 @@
+package htw.berlin.prog2.ha1;
+
+public class Vector {
+    private int[] _data;
+    private int _length;
+    public Vector() {
+        _data = new int[4];
+    }
+    public int get(int position){
+        int datum = this._data[position];
+        return datum;
+    }
+    public void set(int position, int value){
+    }
+    public int getLength(){
+        return this._length;
+    }
+    public void append(int value){
+
+    }
+
+    public static void main(String[] args){
+        Vector vector = new Vector();
+        System.out.println(vector.getLength());
+    }
+}
diff --git a/src/test/java/htw/berlin/prog2/ha1/CalculatorTest.java b/src/test/java/htw/berlin/prog2/ha1/CalculatorTest.java
index ddff0da..7546aff 100644
--- a/src/test/java/htw/berlin/prog2/ha1/CalculatorTest.java
+++ b/src/test/java/htw/berlin/prog2/ha1/CalculatorTest.java
@@ -8,6 +8,25 @@
 @DisplayName("Retro calculator")
 class CalculatorTest {
 
+    @Test
+    @DisplayName("test regular input 12345")
+    void testRegularInput() {
+        //testfall einrichten
+        Calculator calculator = new Calculator();
+        calculator.pressDigitKey(1);
+        calculator.pressDigitKey(2);
+        calculator.pressDigitKey(3);
+        calculator.pressDigitKey(4);
+        calculator.pressDigitKey(5);
+
+        //erwartetes ergebniss
+        String expectedResult = "12345";
+        String actual = calculator.readScreen();
+
+        //vergleich ob test erfolgreich ist
+        assertEquals(expectedResult, actual);
+    }
+
     @Test
     @DisplayName("should display result after adding two positive multi-digit numbers")
     void testPositiveAddition() {
@@ -90,5 +109,60 @@ void testMultipleDecimalDots() {
 
 
     //TODO hier weitere Tests erstellen
+
+    // Aufgabe 2
+    @Test
+    @DisplayName("shouldnt allow multiple oprerrators")
+    void testMultipleOprerrators() {
+        Calculator calc = new Calculator();
+        calc.pressDigitKey(1);
+        calc.pressDigitKey(2);
+        calc.pressBinaryOperationKey("+");
+        calc.pressBinaryOperationKey("-");
+        calc.pressDigitKey(7);
+        calc.pressEqualsKey();
+
+        String expected = "5";
+        String actual = calc.readScreen();
+
+        assertEquals(expected, actual);
+
+    }
+    //Aufgabe 3
+    @Test
+    @DisplayName("should clear completely aufter pressing C")
+    void testClearComplete() {
+        Calculator calc = new Calculator();
+        calc.pressDigitKey(1);
+        calc.pressBinaryOperationKey("+");
+        calc.pressDigitKey(7);
+        calc.pressClearKey();
+        calc.pressDigitKey(8);
+        calc.pressEqualsKey();
+
+        String expected = "9";
+        String actual = calc.readScreen();
+
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    @DisplayName("should cut the .0 out the unary resoult")
+    void testCut() {
+        Calculator calc = new Calculator();
+        calc.pressDigitKey(9);
+        calc.pressDotKey();
+        calc.pressDigitKey(0);
+        calc.pressUnaryOperationKey("√");
+
+        String expected = "3";
+        String actual = calc.readScreen();
+
+        assertEquals(expected, actual);
+    }
 }
 
+
+
+
+