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Year 7 · Summer 1 · Scratch II: Subroutines and lists

Design a game with a flowchart before coding

TheoryPresent ▶

What this lesson covers

Topic 11 Algorithms

KS3 Computing · An algorithm is a precise, step-by-step plan to solve a problem. Computational thinking turns a messy problem into one. Every algorithm is built from just three things: sequence, selection and iteration.

Computational ThinkingCambridge Lower Secondary Computing 0860

You will learn to

  • Identify the main flowchart shapes: start/stop, input/output, process and decision.
  • Create a flowchart of the main loop of a game.
  • Explain why planning on paper first saves time when coding.

Success criteria

  • I can name and draw the main flowchart shapes.
  • I can draw my game's main loop, with an arrow going back up.
  • I can talk the teacher through my flowchart before I start coding.

Key words

Say each word, then read what it means. Every one is in the glossary too.

Algorithm
Precise, ordered, finite steps to solve a problem.
Decomposition
Breaking a problem into smaller ones.
Abstraction
Ignoring detail that doesn't matter for the problem.
Sequence · selection · iteration
Steps one after another. First this, then this.
Pseudocode
Code-like writing for algorithms, without strict rules.
Trace table
Records variable values step by step to check logic.
Variable
A named place in memory that holds a value.

The explanation

Read it here, or open the study page below to go one step at a time with things to try.

Flowcharts

ShapeMeans
Rounded ovalStart / Stop
ParallelogramInput or output
RectangleA process (do something)
DiamondA yes/no decision
Rectangle with double sidesA subroutine
ArrowWhat comes next
e.g.Example

A loop in a flowchart is an arrow going back up to an earlier step.

Study it

Open the study page and go one step at a time.

Topic 11 · Year 7

Algorithms

An algorithm is a precise, step-by-step plan to solve a problem. Computational thinking turns a messy problem into one.

Check yourself

One question at a time. The reason shows after each answer.

Saved on this device.