Unit 02 — Values, Variables & Expressions
Prerequisite: Unit 01 — output, execution, and debugging
Learning goal: Store information in named variables, distinguish data types, and evaluate arithmetic expressions.
Work through the following four lessons in order. Each introduces a focused new skill, builds from earlier material, and includes a coded practice task. Review the example, predict its behavior, then use the browser editor to run and check your work.
| # | Lesson | New skill | Points |
|---|---|---|---|
| 1 | Names for changing information | Variables and assignment | 5 |
| 2 | Calculate with numbers | Integer arithmetic | 5 |
| 3 | Numbers aren’t always text | String, int, float, conversion | 10 |
| 4 | Build: Ticket Cost | Variables and expressions together | 15 |
Open the interactive lessons (Units 02–06). Browser checking is practice; submitted code is graded by GitHub Actions once the corresponding PR contains the new main.py file.
Learning reminders
- Write and run code yourself before revealing hints.
- Use print only in tasks that specifically require console output; for function challenges, use
return. - Explain your reasoning, including how a boundary or unusual input should behave.
- The first two tasks introduce skills, the third combines skills, and the final task is cumulative.