diff --git a/homework/calculate/CMakeLists.txt b/homework/calculate/CMakeLists.txt
index 087714e7..3fcbf95f 100644
--- a/homework/calculate/CMakeLists.txt
+++ b/homework/calculate/CMakeLists.txt
@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.11.0)
 
-set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD 20)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
 include(FetchContent)
@@ -14,7 +14,6 @@ set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
 FetchContent_MakeAvailable(googletest)
 
 # Now simply link against gtest or gtest_main as needed. Eg
-
 project(calculate)
 enable_testing()
 
diff --git a/homework/calculate/calculate.hpp b/homework/calculate/calculate.hpp
index 7a933a25..85f59493 100644
--- a/homework/calculate/calculate.hpp
+++ b/homework/calculate/calculate.hpp
@@ -1,7 +1,20 @@
 #pragma once
+#include <iostream>
 #include <string>
 
 std::string calculate(const std::string& command, int first, int second) {
-    // TODO: Implement your solution here and return proper value
-    return "";
+    if (command == "add") {
+        return std::to_string(first + second);
+    } else if (command == "subtract") {
+        return std::to_string(first - second);
+    } else if (command == "multiply") {
+        return std::to_string(first * second);
+    } else if (command == "divide") {
+        if (second == 0) {
+            return "Division by 0";
+        }
+        return std::to_string(first / second);
+    }
+
+    return "Invalid data";
 }