An algorithm is just a list of steps, in the right order, that gets a job done.
You already use algorithms every day!
🥪 Making a sandwich🦷 Brushing teeth🚌 Taking bus 88 home➗ Long division
A computer can't guess what you mean. So we must tell it every step — clearly, and in order.
👉 In this lesson you will give steps to a robot, spot a bug, and even sort numbers like a computer does. Tap Next to begin!
Every algorithm has steps 🪜
Here is the algorithm for washing your hands. Tap each step to see why the order matters.
Give the robot exact steps 🤖
Robo must reach the star ⭐. Add step-cards to build your program, then press Run. Robo does exactly what you say — nothing more!
Steps must be clear 🔍
A computer has no common sense. "Make it nice" means nothing to it. Compare these two:
❌ Too vague
1. Get some rice. 2. Cook it properly. 3. Serve nicely.
How much rice? How long? The robot freezes. 🥶
✅ Clear enough for a computer
1. Put 1 cup of rice in the pot. 2. Add 2 cups of water. 3. Cook for 15 minutes. 4. Turn off the heat.
Good algorithm steps answer: What? How much? How long? When do I stop?
Your turn: which step is clear enough for a computer?
Order changes everything 🔀
Same steps, wrong order = a mess! Use the ⬆️ ⬇️ buttons to fix this "put on shoes" algorithm, then press Check.
Hunting a bug 🐛
When an algorithm goes wrong, we say it has a bug. Fixing it is called debugging.
Here is the algorithm for drinking a packet drink. One step is in the wrong place. Tap the buggy step!
✅ Fixed algorithm: take packet → peel straw → poke straw in → then drink. Debugging = finding the step that is out of place.
A real algorithm: sorting 📊
Computers sort things all the time — names, prices, scores. Here is Selection Sort: find the smallest, put it first, repeat.
Press "Do one step" to run the algorithm slowly.
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You now know what an algorithm is!
📋 An algorithm is a list of steps that finishes a job.
🔀 Order matters — socks before shoes, straw before sipping.
🔍 Steps must be clear and exact — numbers beat "a while".
🐛 A wrong step is a bug; fixing it is debugging.
📊 Computers use algorithms for real jobs, like sorting numbers.
Try this at home: write the algorithm for making Milo 🥤 — every single step. Then read it to someone and make them follow it exactly. If they get it wrong… you found a bug!
Great thinking today. You're already thinking like a computer scientist! 🌟