basic calculator

README.md

@@ -185,6 +185,11 @@ Notes:
 
 - For running a command with privileges, use `sudo` (for root) or `sudo -u` (for another user). Use `su` or `sudo bash` to actually run a shell as that user. Use `su -` to simulate a fresh login as root or another user.
 
+- For a basic calculator (and of course access to Python in general), use `python` interpreter. For example,
+```
+>>> 2+3
+5
+```
 
 ## Processing files and data