We're sorry but this app doesn't work properly without JavaScript enabled. Please enable it to continue.

This lesson's interactive features are locked, please to keep using them

Spellbook

As you progress through Boot.dev, you might find yourself wanting to:

  • Take notes
  • Review concepts you already learned
  • See more examples of a concept
  • See an example of some syntax you already learned

Your spellbook solves these problems.

It's a searchable cheatsheet of everything you've learned on Boot.dev. As you complete lessons, you'll automatically unlock new pages in your spellbook that can be searched at any time. So, if you know what you're looking for, use your spellbook before chatting with Boots, because using the spellbook costs no items or XP!

Assignment

Competitive Fantasy Quest players – Ballan's Ballers – have won all their games in the elimination round of the tournament. They're now in the finals! Calculate the average score of their 4 games and store it in the average_score variable.

The average (or "mean") is calculated by adding up all the numbers and dividing by how many numbers there are. Which means first we need to add up all the scores, then divide by 4.

Let's use our spellbook to recall the syntax we need:

    • Look at the bottom-right of the lesson text, you'll see a toggle to switch from Boots to your spellbook. Flip the switch to open your spellbook.
    • On mobile, it's the last tab at the top of the screen.

Complete the lesson using your spellbook as a reference