diff --git a/README.md b/README.md
index 643700d..619833c 100644
--- a/README.md
+++ b/README.md
@@ -1 +1,3 @@
-# advprogram
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+# advprogram
+
+Quàng Thế Anh- 22026554
diff --git a/lec1-simplecalculator/Simple_Caculator_22026554.cpp b/lec1-simplecalculator/Simple_Caculator_22026554.cpp
new file mode 100644
index 0000000..a3ee354
--- /dev/null
+++ b/lec1-simplecalculator/Simple_Caculator_22026554.cpp
@@ -0,0 +1,93 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+double arithmetic(double num1, double num2, char op)
+{
+    switch (op) {
+    case '+':
+        return num1 + num2;
+    case '-':
+        return num1 - num2;
+    case 'x':
+         return num1 * num2;
+    case '/':
+        if (num2 == 0) {
+            cout << "Invalid divisor" << endl;
+            exit(1);
+        }
+        else
+            return num1 / num2;
+    case '%':
+        if (num2 == 0 || num2 != (int)num2 || num1 != (int)num1) {
+            cout << "Invalid divisor" << endl;
+            exit(1);
+        }
+        else{
+            return (int)num1 % (int)num2;
+        }
+    default:
+        cout << "Invalid operator" << endl;
+        exit(1);
+    }
+}
+
+double luonggiac(double num, string n)
+{
+    if (n == "cos"){
+        return cos(num);
+    }
+    else if (n == "sin"){
+        return sin(num);
+    }
+    else if (n == "tan"){
+        return tan(num);
+    }
+    else if (n == "cot"){
+        return (1/tan(num));
+    }
+    else if (n == "sqrt"){
+        if (num > 0){
+            return sqrt(num);
+        }
+        else{
+            cout<< "Invalid";
+            exit(1);
+        }
+    }
+}
+
+int main(int argc, char* argv[])
+{
+    if(argc == 4){
+        double  num1, num2;
+        char op;
+        num1 = atof(argv[1]);
+        op = argv[2][0];
+        num2 = atof(argv[3]);
+        cout<< arithmetic(num1, num2, op);
+    }
+    else if (argc == 3){
+        string n = argv[1];
+        int s = n.length();
+        if (s == 3){
+            if ((n != "cos") && (n != "sin") && (n != "tan" && n != "cot")){
+                cout<< "Invalid operator";
+                exit(1);
+            }
+        }
+        if (s == 4){
+            if (n != "sqrt"){
+                cout<< "Invalid operator";
+                exit(1);
+            }
+        }
+        double num;
+        num = atof(argv[2]);
+        cout<< luonggiac(num, n);
+    }
+    else {
+        cout<< "Invalid operator";
+        exit(1);
+    }
+    return 0;
+}
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