diff --git a/homework/calculate/calculate.hpp b/homework/calculate/calculate.hpp
index 7a933a25..fca9c696 100644
--- a/homework/calculate/calculate.hpp
+++ b/homework/calculate/calculate.hpp
@@ -2,6 +2,21 @@
 #include <string>
 
 std::string calculate(const std::string& command, int first, int second) {
-    // TODO: Implement your solution here and return proper value
-    return "";
+    int wynik = 0;
+
+    if (command == "add") {
+	 wynik = first + second;
+    } else if (command == "subtract") {
+	 wynik = first - second;
+    } else if (command == "multiply") {
+        wynik = first * second;
+    } else if (command == "divide" && second != 0) {
+        wynik = first / second;
+    } else if (command == "divide" && second == 0) {
+        return "Division by 0";
+    } else {
+	 return "Invalid data";
+    }
+    std::string s = std::to_string(wynik);
+    return s;
 }