diff --git a/Axel/src/de/hs_mannheim/informatik/spreadsheet/Spreadsheet.java b/Axel/src/de/hs_mannheim/informatik/spreadsheet/Spreadsheet.java
index c5ad4e9..ae7f922 100644
--- a/Axel/src/de/hs_mannheim/informatik/spreadsheet/Spreadsheet.java
+++ b/Axel/src/de/hs_mannheim/informatik/spreadsheet/Spreadsheet.java
@@ -120,22 +120,27 @@ public class Spreadsheet {
 		String formula = cells[row][col].getFormula();
 		String result = "";
 
-		if (formula.startsWith("SUMME("))  // e.g. SUMME(A3:A8)
+		if (formula.startsWith("SUMME("))
 			if(formula.length()==14) 
 				result = "" + sum(formula.substring(6, 9), formula.substring(10, 13));
 			else if(formula.length()==13) 
 				result = "" + sum(formula.substring(6, 8), formula.substring(9, 12));
 			else 
 				result = "" + sum(formula.substring(6, 8), formula.substring(9, 11));
-		else if (formula.startsWith("PRODUKT("))  // e.g. PRODUKT(A3:B9)
+		else if (formula.startsWith("PRODUKT("))
 			if(formula.length()==16) 
 				result = "" + product(formula.substring(8, 11), formula.substring(12, 15));
 			else if(formula.length()==15) 
 				result = "" + product(formula.substring(8, 10), formula.substring(11, 14));
 			else 
 				result = "" + product(formula.substring(8, 10), formula.substring(11, 13));
-		else if (formula.startsWith("MITTELWERT("))  // e.g. MITTELWERT(A3:A5)
-			result = "TODO"; // TODO
+		else if (formula.startsWith("MITTELWERT("))
+			if(formula.length()==19) 
+				result = "" + average(formula.substring(11, 14), formula.substring(15, 18));
+			else if(formula.length()==18) 
+				result = "" + average(formula.substring(11, 13), formula.substring(14, 17));
+			else 
+				result = "" + average(formula.substring(11, 13), formula.substring(14, 16));
 		else if (formula.startsWith("STABW("))  // e.g. STABW(C6:D8) -> Standardabweichung
 			result = "TODO"; // TODO
 		else if (formula.startsWith("MIN("))  // e.g. MIN(C13:H13) -> größter Wert
@@ -160,7 +165,7 @@ public class Spreadsheet {
 	 * @return The sum calculated.
 	 */
 	private long sum(String startCellName, String endCellName) {
-		int sum=0;
+		long sum=0;
 		for(int i=startCellName.charAt(0)-'A'; i<=endCellName.charAt(0)-'A'; i++) {
 			for(int j=Integer.parseInt(startCellName.substring(1))-1; j<=Integer.parseInt(endCellName.substring(1))-1; j++) {
 				if(cells[j][i].isEmpty()) {
@@ -172,7 +177,7 @@ public class Spreadsheet {
 		return sum;
 	}
 	private long product(String startCellName, String endCellName) {
-		int product=1;
+		long product=1;
 		for(int i=startCellName.charAt(0)-'A'; i<=endCellName.charAt(0)-'A'; i++) {
 			for(int j=Integer.parseInt(startCellName.substring(1))-1; j<=Integer.parseInt(endCellName.substring(1))-1; j++) {
 				if(cells[j][i].isEmpty()) {
@@ -183,6 +188,20 @@ public class Spreadsheet {
 		}
 		return product;
 	}
+	private long average(String startCellName, String endCellName) {
+		long average=0;
+		int counter=0;
+		for(int i=startCellName.charAt(0)-'A'; i<=endCellName.charAt(0)-'A'; i++) {
+			for(int j=Integer.parseInt(startCellName.substring(1))-1; j<=Integer.parseInt(endCellName.substring(1))-1; j++) {
+				if(cells[j][i].isEmpty()) {
+					continue;
+				}
+				average+=Integer.parseInt(cells[j][i].getValue());
+				counter++;
+			}
+		}
+		return (long) average/counter;
+	}
 
 	/**
 	 * This method calculates the result of a "normal" algebraic expression. It only needs to support