What you'll build
- A programming setup that you can type in and get answers to basic calculations.
What you'll learn
- How to type and change code in a playground.
- Where to look for the results of your work.
- How to add notes that will help you remember what your code means.
- What it looks like if something goes wrong.
Key vocabulary
Introduction
Playgrounds allow you to experiment with programming ideas without building an entire app. You’ll write some code, watch it run, think about it a bit, change some lines, and watch it run again. Down the road, you can turn your successful experiments into a fully featured app. But for now, just play—and learn.
Go Build
Open the Playground Basics.playground file in your course resources and follow the instructions.

Reflection Questions
What surprised you most about using the playground in this lesson?
What other kinds of calculations could you store and run in a playground?
Summary
You worked on simple problems in a real programming environment and saw the results of the computer doing some work for you. You even saw an error from some mistyped instructions and checked where it was coming from so that you could fix the issue. Now you’re ready to start one of the most fundamental concepts in programming—using names to label your work. Labeling your work allows you to reuse and remix the results so the computer can solve increasingly difficult problems.