diff --git a/src/main/java/tdd/setup/Calculator.java b/src/main/java/tdd/setup/Calculator.java
index 171f6d6..1e63c78 100644
--- a/src/main/java/tdd/setup/Calculator.java
+++ b/src/main/java/tdd/setup/Calculator.java
@@ -3,34 +3,47 @@
 // behaviour inspired by https://www.online-calculator.com/
 public class Calculator {
 
-    private String screen = "0";
+    private String screen = "";
 
     private double latestValue;
 
     private String latestOperation = "";
 
+    private boolean clearScreen = false;
+
+
     public String readScreen() {
         return screen;
     }
-    public void pressDigitKey(int digit) {
+
+   public void pressDigitKey(int digit) {
         if(digit > 9 || digit < 0) throw new IllegalArgumentException();
 
-        if(latestOperation.isEmpty()) {
-            screen = screen + digit;
-        } else {
-            latestValue = Double.parseDouble(screen);
-            screen = Integer.toString(digit);
-        }
+       //new code, added new variable clear screen, this variable is set, when the
+       //operation button is pressed
+       if (clearScreen) {
+           screen = Integer.toString(digit);
+           clearScreen = false;
+       } else {
+           screen = screen + Integer.toString(digit);
+       }
+
+       if (latestOperation.isEmpty()){
+           latestValue = Double.parseDouble(screen);
+       }
     }
 
     public void pressClearKey() {
         screen = "0";
         latestOperation = "";
         latestValue = 0.0;
+        clearScreen = false;
     }
 
     public void pressOperationKey(String operation)  {
         latestOperation = operation;
+        clearScreen = true;
+
     }
 
     public void pressDotKey() {
@@ -41,12 +54,15 @@ public void pressNegative() {
         screen = screen.startsWith("-") ? screen.substring(1) : "-" + screen;
     }
 
+   // public void pressTwoOperationKeys
+
     public void pressEquals() {
         var result = switch(latestOperation) {
             case "+" -> latestValue + Double.parseDouble(screen);
             case "-" -> latestValue - Double.parseDouble(screen);
             case "x" -> latestValue * Double.parseDouble(screen);
             case "/" -> latestValue / Double.parseDouble(screen);
+
             default -> throw new IllegalArgumentException();
         };
         screen = Double.toString(result);
diff --git a/src/test/java/tdd/setup/CalculatorTest.java b/src/test/java/tdd/setup/CalculatorTest.java
index 3bf16e9..4ae3ee1 100644
--- a/src/test/java/tdd/setup/CalculatorTest.java
+++ b/src/test/java/tdd/setup/CalculatorTest.java
@@ -7,13 +7,35 @@
 @DisplayName("Retro calculator")
 class CalculatorTest {
     @Test
-    @DisplayName("should display result after adding two positive numbers")
-    void calculatorCanDoTwoPlusTwo() {
+    @DisplayName("should display results after 5 - 4")
+    void calculatorCanDo5Minus4(){
         Calculator calc = new Calculator();
-        calc.pressDigitKey(2);
+        calc.pressDigitKey(5);
+        calc.pressOperationKey("-");
+        calc.pressDigitKey(4);
+        calc.pressEquals();
+        assertEquals("1", calc.readScreen());
+    }
+    @Test
+    @DisplayName("should display results after press 8 ,., 5")
+    void calculatorCanDoDoubleNumber(){
+        Calculator calc = new Calculator();
+        calc.pressDigitKey(8);
+        calc.pressDotKey();
+        calc.pressDigitKey(5);
+        assertEquals("8.5", calc.readScreen());
+    }
+    @Test
+    @DisplayName("should display results after ")
+    void calculatorCanDoNumber(){
+        Calculator calc = new Calculator();
+        calc.pressDigitKey(5);
         calc.pressOperationKey("+");
-        calc.pressDigitKey(2);
+        calc.pressDigitKey(1);
+        calc.pressDigitKey(5);
         calc.pressEquals();
-        assertEquals("4", calc.readScreen());
+       assertEquals("20", calc.readScreen());
     }
+
+
 }