diff --git a/include/Expression.hpp b/include/Expression.hpp
new file mode 100644
index 0000000..b832e72
--- /dev/null
+++ b/include/Expression.hpp
@@ -0,0 +1,36 @@
+/*
+// Copyright (c) 2017 Intel Corporation
+// Copyright (c) 2022 IBM Corp.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+*/
+
+#pragma once
+
+#include <optional>
+#include <string>
+
+namespace expression
+{
+enum class Operation
+{
+    addition,
+    division,
+    multiplication,
+    subtraction,
+    modulo,
+};
+
+std::optional<Operation> parseOperation(std::string& op);
+int evaluate(int a, Operation op, int b);
+} // namespace expression