diff --git a/sk2/calculator.h b/sk2/calculator.h
new file mode 100644
index 0000000..6f1b584
--- /dev/null
+++ b/sk2/calculator.h
@@ -0,0 +1,8 @@
+#ifndef _CALCULATOR_
+#define _CALCULATOR_
+#include <stdio.h>
+#include <math.h>
+
+double evaluateExpression(char* expression, int configuration);
+
+#endif
\ No newline at end of file