diff --git a/lec0-gameover/GameOver2.cpp b/lec0-gameover/GameOver2.cpp
index 5d3b307..a49dd40 100644
--- a/lec0-gameover/GameOver2.cpp
+++ b/lec0-gameover/GameOver2.cpp
@@ -1,5 +1,6 @@
 // GameOver2.cpp
 #include <iostream>
+
 using namespace std;
 
 int main()
diff --git a/lec0-gameover/Game_Over_22021212.cpp b/lec0-gameover/Game_Over_22021212.cpp
new file mode 100644
index 0000000..63be9bc
--- /dev/null
+++ b/lec0-gameover/Game_Over_22021212.cpp
@@ -0,0 +1,7 @@
+#include <iostream>
+using namespace std;
+
+ int main(){
+    cout << "Game Over !" << endl;
+    return 0;
+ }
diff --git a/lec1-simplecalculator/SimpleCalculator_0_1.cpp b/lec1-simplecalculator/SimpleCalculator_0_1.cpp
index 108a681..b94678d 100755
--- a/lec1-simplecalculator/SimpleCalculator_0_1.cpp
+++ b/lec1-simplecalculator/SimpleCalculator_0_1.cpp
@@ -6,7 +6,6 @@ int main()
 {
     int num1, num2;
     char op;
-
     cin >> num1 >> op >> num2;
     switch (op)
     {
diff --git a/lec1-simplecalculator/SimpleCalculator_0_2_22021212.cpp b/lec1-simplecalculator/SimpleCalculator_0_2_22021212.cpp
new file mode 100644
index 0000000..4a7bffe
--- /dev/null
+++ b/lec1-simplecalculator/SimpleCalculator_0_2_22021212.cpp
@@ -0,0 +1,113 @@
+//simple_calculator.cpp
+#include <iostream>
+#include <cstdlib>
+#include <string>
+#include <math.h>
+
+using namespace std;
+
+double arithmetic(double &num1,double &num2, char &op);
+double arithmetic(string &func,double &num);
+
+int main(int argc, char* argv[])
+{
+    double num1, num2, result;
+    char op;
+    if(argc == 3){ // Xu ly ham luong giac va can bac 2
+        string func = argv[1];
+        double num = atof(argv[2]);
+        cout << arithmetic(func,num) << endl;
+    }else{  // Xu ly tinh toan thong thuong
+    num1 = atof(argv[1]);
+    op = argv[2][0];
+    num2 = atof(argv[3]);
+    cout << arithmetic(num1, num2, op) << endl;
+    }
+    return 0;
+}
+
+double arithmetic(double &num1,double &num2, char &op)
+{   double result;
+    switch (op)
+    {
+    case '+':
+        result =  num1 + num2;
+        break;
+    case '-':
+        result = num1 - num2;
+        break;
+    case 'x':
+        result =  num1 * num2;
+        break;
+    case '/':
+        if (num2 == 0)
+        {
+            cout << "Invalid divisor" << endl;
+            exit(1);
+        }
+        else
+            result = num1 / num2;
+            break;
+    case '%':
+        if (num2 == 0)
+        {
+            cout << "Invalid divisor" << endl;
+            exit(1);
+        }
+        else if (num1-(int)num1 == 0 && num2 - (int)num2 == 0){
+            result = (int)num1 % (int)num2;
+            break;
+        }
+        else{
+            cout << "Invalid number (float numbers aren't allowed with this operator)" << endl;
+            exit(1);
+        }
+    default:
+        cout << "Invalid operator" << endl;
+        exit(1);
+    }
+    if(abs(result) > 1e6){
+        cout << "Result exceeded limit" << endl;
+    }else{
+        return result;
+    }
+    return 0;
+}
+
+double arithmetic(string &func,double &num){
+    if(abs(num) > 1e6){
+        cout << "Input exceed limit" << endl;
+        return 0;
+    }
+
+    if(func.compare("cos") == 0){
+        return cos(num);
+    }else if(func.compare("sin") == 0){
+        return sin(num);
+    }else if(func.compare("tan") == 0 || func.compare("tg") == 0){
+        if(abs(cos(num)) < 1e-9){
+            cout << "Invalid input" << endl;
+        }else
+        return tan(num);
+    }else if(func.compare("cot") == 0 || func.compare("cotg") == 0){
+        if(abs(sin(num)) < 1e-9){
+            cout << "Invalid input" << endl;
+        }else
+        return 1/tan(num);
+    }else if(func.compare("sqrt") == 0 ){
+        if(num < 0){
+            cout << "Invalid input square root function" << endl;
+            return 0;
+        }else{
+            return sqrt(num);
+        }
+    }
+    else{
+    cout << "Invalid Function" << endl;
+    }
+    return 0;
+}
+
+
+
+//Modified by 22021212_LeVuVietAnh