diff --git a/Rechner/.classpath b/Rechner/.classpath
index 57bca72..d54800d 100644
--- a/Rechner/.classpath
+++ b/Rechner/.classpath
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <classpath>
-	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-17">
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-11">
 		<attributes>
 			<attribute name="module" value="true"/>
 		</attributes>
diff --git a/Rechner/.settings/org.eclipse.jdt.core.prefs b/Rechner/.settings/org.eclipse.jdt.core.prefs
index 8c9943d..f2525a8 100644
--- a/Rechner/.settings/org.eclipse.jdt.core.prefs
+++ b/Rechner/.settings/org.eclipse.jdt.core.prefs
@@ -1,8 +1,8 @@
 eclipse.preferences.version=1
 org.eclipse.jdt.core.compiler.codegen.inlineJsrBytecode=enabled
-org.eclipse.jdt.core.compiler.codegen.targetPlatform=17
+org.eclipse.jdt.core.compiler.codegen.targetPlatform=11
 org.eclipse.jdt.core.compiler.codegen.unusedLocal=preserve
-org.eclipse.jdt.core.compiler.compliance=17
+org.eclipse.jdt.core.compiler.compliance=11
 org.eclipse.jdt.core.compiler.debug.lineNumber=generate
 org.eclipse.jdt.core.compiler.debug.localVariable=generate
 org.eclipse.jdt.core.compiler.debug.sourceFile=generate
@@ -11,4 +11,4 @@ org.eclipse.jdt.core.compiler.problem.enablePreviewFeatures=disabled
 org.eclipse.jdt.core.compiler.problem.enumIdentifier=error
 org.eclipse.jdt.core.compiler.problem.reportPreviewFeatures=warning
 org.eclipse.jdt.core.compiler.release=enabled
-org.eclipse.jdt.core.compiler.source=17
+org.eclipse.jdt.core.compiler.source=11
diff --git a/Rechner/src/Calculator.java b/Rechner/src/Calculator.java
index 582c5cb..8f2e2af 100644
--- a/Rechner/src/Calculator.java
+++ b/Rechner/src/Calculator.java
@@ -1,12 +1,46 @@
 
 public class Calculator {
-Node<Symbol> erzeugeBeispielBaum() {
-	 Node<Symbol> root = new Node<Symbol>(new Symbol("+")); 
-root.left = new Node<Symbol>(new Symbol("3")); 
-root.right = new Node<Symbol>(new Symbol("*")); 
-root.right.left = new Node<Symbol>(new Symbol("8")); 
-return root; 
+	Node<Symbol> erzeugeBeispielBaum() {
+		Node<Symbol> root = new Node<Symbol>(new Symbol("*"));
+		root.left = new Node<Symbol>(new Symbol("3"));
+		root.right = new Node<Symbol>(new Symbol("+"));
+		root.right.left = new Node<Symbol>(new Symbol("5"));
+		root.right.right = new Node<Symbol>(new Symbol("8"));
+		return root;
 
+	}
+
+	public int berechne(Node<Symbol> n) {
+		if (n.left == null) {
+			return n.content.getInt();
+
+		} else {
+			int links = berechne(n.left);
+			int rechts = berechne(n.right);
+			if (n.content.istMal()) {
+				return links * rechts;
+			} else {
+				return links + rechts;
+			}
+		}
+	}
+
+	public void infixAusgeben(Node<Symbol> n) {
+		if (n.left == null) {
+			System.out.print(n.content);
+		} else {
+			infixAusgeben(n.left); 
+				System.out.print(n.content);
+				if(n.content.istMal() && n.right.content.istPlus()) {
+				System.out.print("(");
+				infixAusgeben(n.right);
+				System.out.print(")");
+				}
+				else {
+				infixAusgeben(n.right);
+		
+		}
+	}
 
 }
 }
diff --git a/Rechner/src/Symbol.java b/Rechner/src/Symbol.java
index cd8a8c2..eef0ce3 100644
--- a/Rechner/src/Symbol.java
+++ b/Rechner/src/Symbol.java
@@ -5,7 +5,7 @@ public Symbol(String _s) {
 	this.s = _s; 
 }
 public boolean istMal() {
-	return s == "x"; 
+	return s == "*"; 
 }
 public boolean istPlus() {
 	return s == "+"; 
@@ -19,5 +19,7 @@ public boolean istZhal()  {
 public int getInt() {
 	return Integer.parseInt(s); 
 }
-
+public String toString() {
+	return s; 
+}
 }
diff --git a/Rechner/src/Test.java b/Rechner/src/Test.java
index ceb94cf..beb7ed2 100644
--- a/Rechner/src/Test.java
+++ b/Rechner/src/Test.java
@@ -4,7 +4,9 @@ public class Test {
 	public static void main(String[] args) {
 	Calculator c = new Calculator(); 
 	Node<Symbol> root = c.erzeugeBeispielBaum(); 
-
+	int ergebnis  = c.berechne(root); 
+	System.out.println( ergebnis);
+	c.infixAusgeben(root);
 	}
 
 }