Computing · Stage 6

How the CPU Works

Coding & Systems · systems — the three steps a CPU repeats billions of times a second: fetch, decode, execute

✦ Computing📘 Stage 6 · S6⏱ ~13 min🧒 Ages 10–12★ Free to start

I can explain the fetch–decode–execute cycle.

📖

Kavi and the Tiny Fast Worker

Kavi tapped a key and — poof — the letter appeared on the screen in a blink. "How did it know what to do so fast?" Kavi hooted. The secret is a tiny worker inside every computer called the CPU — the processor. For every single thing the computer does, the CPU repeats the same three steps, faster than you can blink: it FETCHES the next instruction, DECODES what it means, then EXECUTES it. "Fetch… decode… execute… fetch… decode… execute…" — billions of times a second!

🎓

What your child will learn

1The parts that run the cycleThe CPU (processor) is the brain of the computer. A few parts inside it work together to run the cycle. Tap each one to see what it does.

2Fetch, decode, execute — over and overEvery instruction goes through the same three steps, always in this order. Tap each step to hear it.

3Sort each job into its stepEach job below happens in one step of the cycle. Fetch = get the instruction. Decode = work out what it means. Execute = carry it out. Tap the right step for each.

4Decode works it OUT · Execute carries it OUTThis is the step people muddle most. Tap each card to see the difference.

🔍

A peek inside

A CPU repeats the same three steps for every instruction. Name them in order, and say what happens in each.

fetch → decode → execute

Try this at home: What do the three letters F, D, E of the cycle stand for?

Ready to play and learn?

Start the free interactive lesson, or print the handout for screen-free play.

Start the free lesson →⬇ Download PDF

Part of Computing · Stage 6 · S6 on KAVI Academy — a secular, whole-child learning platform for ages 5–12.