Variables and printing

1. What is this?

A program is instructions the computer runs top to bottom. A variable is a named box that holds a value so you can reuse it. With let name = "Ava" you create a box called name holding the text Ava. console.log(...) prints a value to the output so you can see it.

2. Why do we use it?

Every app stores things: usernames, totals, settings. Variables are that storage. Logging is how you check what your program is doing.

3. Syntax breakdown

• let name = "Ava";

  let creates a variable. name is its label. = stores the value "Ava" in it.

• let age = 28;

  Numbers need no quotes. Text (strings) does.

• console.log(name);

  Prints the value of name to the output panel.

5. Common mistakes

• Forgetting quotes around text: let name = Ava looks for a variable called Ava.
• Using = (store) when you mean === (compare) — covered in the next module.
• console.log(name) after misspelling the variable (Name vs name — case matters).

Practice task

Create a variable city with your city, and log "I live in <city>."

Press Run to see output.

Mini quiz

3 questions. Answer, then check.

1. 1. What is a variable?

   A named box holding a valueA kind of loopAn error message

2. 2. Which line creates a text variable correctly?

   let city = "Berlin";let city = Berlin;city "Berlin" =;

3. 3. What does console.log do?

   Prints a value to the outputSaves a fileCreates a variable