Lesson 4: Step by step

After drawing an image made from simple shapes, decomposition skills are required to break down the process into steps to enable someone else to replicate the drawing

Learning objective

  • To understand and be able to explain what decomposition is

National curriculum links

Pupils should be taught to:

  • Understand what algorithms are, how they are implemented as programs on digital devices, and that programs execute by following precise and unambiguous instructions
  • Create and debug simple programs
  • Use logical reasoning to predict the behaviour of simple programs

Success criteria

Cross-curricular links

Before the lesson

Download classroom resources

Attention grabber

Main event


Pupils needing extra support: May need help holding shapes whilst drawing around them and should be encouraged to make a simpler design with fewer shapes or stages.


Pupils working at greater depth: Should be encouraged to make a more complex design, reminding them that they will need to be able to record how it was designed.

Wrapping up

Assessing pupils' progress and understanding


Created by:
Siobhan Morgan,  
Computing specialist
Head of Computing at Exeter Junior School, Siobhan Morgan has nine years of computing teaching experience as well as experience from her role of ‘Subject Genius for Computing’ on TES. Siobhán enjoys spending time with her family and searching for the Gruffalo…
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