Computing · Stage 5

Design an Algorithm

Programs & Judgement · algorithm design · build a plan with sequence, selection and iteration

✦ Computing📘 Stage 5 · S5⏱ ~13 min🧒 Ages 9–10★ Free to start

I can design with sequence, selection and iteration.

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Kavi Designs the Whole Plan

Kavi wanted to build a quiz game. "I need a plan the computer can follow all by itself," said Kavi. A plan like that is called an algorithm. Kavi found that every algorithm is built from just three kinds of steps. Sequence — do things in order, one after another. Selection — choose with IF–THEN. Iteration — repeat with a loop. "So I set the score, then repeat for every question, and if the answer is right I add a point," Kavi hooted. "Sequence, selection and iteration — put them together and I can design anything!"

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What your child will learn

1Every algorithm is built from three kinds of stepAn algorithm is a clear plan a computer can follow. Amazingly, every plan is built from just three building blocks. Tap each one to hear its job.

2One plan that uses all threeHere is Kavi's quiz-scoring algorithm. It puts steps in order, repeats with a loop, and makes a choice with IF. Press ▶ Run and watch the whole plan work.

3Which building block is each step?

4Run the algorithm in your headRead each little algorithm, follow the steps in order, and predict what happens. Reveal to check, then try the next one.

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A peek inside

Which building block is this step? REPEAT 4 times: feed the fish

it does the same action again and again — that is a loop

Try this at home: A clear plan a computer can follow is called an ____.

Ready to play and learn?

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

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Part of Computing · Stage 5 · S5 on KAVI Academy — a secular, whole-child learning platform for ages 5–12.