# 3 An Informal Introduction to Python

In the following examples, input and output are distinguished by the presence or absence of prompts (`>>>` and `...`): to repeat the example, you must type everything after the prompt, when the prompt appears; lines that do not begin with a prompt are output from the interpreter.Note that a secondary prompt on a line by itself in an example means you must type a blank line; this is used to end a multi-line command.

- 3.1 Using Python as a Calculator
  - 3.1.1 Numbers
  - 3.1.2 Strings
  - 3.1.3 Lists
- 3.2 First Steps Towards Programming