Variables — labelled boxes that store things

⏱ 20 min learn Ages 9 & 12

💡 The big idea

A variable is a named box that stores a value. You can put anything in it, look at it, change it, and use it in calculations. Variables are the building blocks of every program ever written.

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The labelled box analogy

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"A variable is like a labelled box. You put something inside, label it, and then use the label whenever you need what's inside. In Python: name = 'Alex' creates a box labelled name with 'Alex' inside."

name = "Alex" # string — text goes in quotes age = 12 # integer — whole number, no quotes height = 1.54 # float — decimal number print("Hello,", name) print("You are", age, "years old")

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Build the My Info program

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Write a Python program that asks for my name, age, and favourite colour using input(), then prints a fun personalised sentence using all three variables. Explain each line for a 10-year-old beginner.

🗣 Try: Change the value stored in one variable and run the program again. Does the output change? What happens if you try to add a string and a number together?

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Lesson quiz — test yourself!

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Wrap-up discussion questions

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1️⃣ What are the three variable types you learned today?

2️⃣ Why do strings need quote marks but integers don't?

3️⃣ What happens if you try to use a variable name that doesn't exist?