diff --git a/app/src/main/java/htw/berlin/prog2/.DS_Store b/app/src/main/java/htw/berlin/prog2/.DS_Store
new file mode 100644
index 0000000..cf1c5cf
Binary files /dev/null and b/app/src/main/java/htw/berlin/prog2/.DS_Store differ
diff --git a/app/src/main/java/htw/berlin/prog2/ha1/Calculator.java b/app/src/main/java/htw/berlin/prog2/ha1/Calculator.java
index 84c04f2..06a1c41 100644
--- a/app/src/main/java/htw/berlin/prog2/ha1/Calculator.java
+++ b/app/src/main/java/htw/berlin/prog2/ha1/Calculator.java
@@ -45,9 +45,14 @@ 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;
+    }
+    public String giveLatestValue(){
+        return Double.toString(latestValue);
     }
 
     /**
@@ -83,7 +88,7 @@ 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);
     }
 
     /**
@@ -130,4 +135,4 @@ public void pressEqualsKey() {
         if(screen.endsWith(".0")) screen = screen.substring(0,screen.length()-2);
         if(screen.contains(".") && screen.length() > 11) screen = screen.substring(0, 10);
     }
-}
+}
\ No newline at end of file
diff --git a/app/src/test/java/htw/berlin/prog2/.DS_Store b/app/src/test/java/htw/berlin/prog2/.DS_Store
new file mode 100644
index 0000000..7e0d1f5
Binary files /dev/null and b/app/src/test/java/htw/berlin/prog2/.DS_Store differ
diff --git a/app/src/test/java/htw/berlin/prog2/ha1/CalculatorTest.java b/app/src/test/java/htw/berlin/prog2/ha1/CalculatorTest.java
index ddff0da..e6230c0 100644
--- a/app/src/test/java/htw/berlin/prog2/ha1/CalculatorTest.java
+++ b/app/src/test/java/htw/berlin/prog2/ha1/CalculatorTest.java
@@ -90,5 +90,53 @@ void testMultipleDecimalDots() {
 
 
     //TODO hier weitere Tests erstellen
+    @Test
+    @DisplayName("should calculate the result of multiple additions sequentially")
+    void testMultipleAdditions() {
+        Calculator calc = new Calculator();
+        calc.pressDigitKey(1);
+        calc.pressBinaryOperationKey("+");
+        calc.pressDigitKey(2);
+        calc.pressEqualsKey(); // Ergebnis: 3
+        calc.pressBinaryOperationKey("+");
+        calc.pressDigitKey(3);
+        calc.pressEqualsKey(); // Ergebnis: 6
+        String expected = "6";
+        String actual = calc.readScreen();
+        assertEquals(expected, actual);
+    }
+
+
+
+    @Test
+    @DisplayName("should display result after getting the scare root of 4")
+    void testSquareRootOfFour() {
+        Calculator calc = new Calculator();
+
+        calc.pressDigitKey(4);
+        calc.pressUnaryOperationKey("√");
+
+        String expected = "2";
+        String actual = calc.readScreen();
+
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    @DisplayName("the latest value should not be deleted after pressing the Clear Key once")
+    void testCeKey() {
+        Calculator calc = new Calculator();
+
+        calc.pressDigitKey(1);
+        calc.pressBinaryOperationKey("+");
+        calc.pressDigitKey(1);
+        calc.pressClearKey();
+
+        String expected = "1.0";
+        String actual = calc.giveLatestValue();
+
+        assertEquals(expected, actual);
 }
 
+
+}