diff --git a/Aufgabe 7/main.cpp b/Aufgabe 7/main.cpp
index c111df4..f29bc9f 100644
--- a/Aufgabe 7/main.cpp	
+++ b/Aufgabe 7/main.cpp	
@@ -55,7 +55,18 @@ std::vector<Equation> parseEquations(std::vector<std::string>& stringEquations)
     return equations;
 }
 
-bool backtrack(int index, uint64_t current_value, const Equation& equation) {
+uint64_t concatenate(uint64_t a, uint64_t b) {
+    uint64_t temp = b;
+    while (temp > 0) {
+        a *= 10;   // Multipliziere a mit 10, um Platz für die nächste Ziffer zu schaffen
+        temp /= 10; // Teile temp durch 10, um die Länge zu bestimmen
+    }
+
+    return a + b;  // Verkette die Zahlen
+}
+
+
+bool backtrack(int index, uint64_t current_value, const Equation& equation, bool enableConcatOp) {
     // Basisfall: We have processed all numbers
     if(index == equation.numbers.size()) {
         return current_value == equation.testValue;
@@ -65,25 +76,31 @@ bool backtrack(int index, uint64_t current_value, const Equation& equation) {
     uint64_t next_number = equation.numbers.at(index);
 
     // Option 1 : Add the next number
-    if(backtrack(index + 1, current_value + next_number, equation)) {
+    if(backtrack(index + 1, current_value + next_number, equation, enableConcatOp)) {
         return true;
     }
 
-    if(backtrack(index + 1, current_value * next_number, equation)) {
+    if(backtrack(index + 1, current_value * next_number, equation, enableConcatOp)) {
         return true;
     }
 
+    if(enableConcatOp) {
+        if(backtrack(index + 1, concatenate(current_value, next_number), equation, enableConcatOp)) {
+            return true;
+        }
+    }
+
     return false;
 }
 
-bool isEquationCorrect(const Equation& equation) {
-    return backtrack(1, equation.numbers[0], equation);
+bool isEquationCorrect(const Equation& equation, bool enableConcatOp) {
+    return backtrack(1, equation.numbers[0], equation, enableConcatOp);
 }
 
-std::vector<Equation> determineCorrectEquations(std::vector<Equation>& equations) {
+std::vector<Equation> determineCorrectEquations(std::vector<Equation>& equations, bool enableCocatOp) {
     std::vector<Equation> correctEquations;
     for(const auto& equation : equations) {
-        if(isEquationCorrect(equation)) {
+        if(isEquationCorrect(equation, enableCocatOp)) {
             correctEquations.push_back(equation);
         }
     }
@@ -101,7 +118,11 @@ uint64_t calcTotalCalibResult(std::vector<Equation>& equations) {
 int main() {
     std::vector<std::string> input = readTextFromFile("../input.txt");
     std::vector<Equation> equatons = parseEquations(input);
-    std::vector<Equation> correctEquations = determineCorrectEquations(equatons);
+    std::vector<Equation> correctEquations = determineCorrectEquations(equatons, false);
     std::cout << "The total calibration value is " << calcTotalCalibResult(correctEquations) << std::endl;
+    std::vector<Equation> correctEquationsConcat = determineCorrectEquations(equatons, true);
+    std::cout << "The total calibration with Concat Op value is " << calcTotalCalibResult(correctEquationsConcat) << std::endl;
+
+    std::cout << "Test: " << concatenate(15, 6) << std::endl;
     return 0;
 }