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Decomposition

Sixth graders learn decomposition — breaking a big, hard problem into smaller parts you can actually solve. “Build a game” is too big at once; “draw one character” is a doable piece. They sort big problems from their smaller parts, then decompose a problem of their own.

Grade 6Decomposition50 minutes1 class periodCSTA / ISTEExplicit teaching4 StandardsCSTA
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Lesson at a Glance

Everything you need before the bell rings

Learning Objectives

Students will be able to…

  • ✓Explain decomposition.
  • ✓Tell a big problem from a smaller part.
  • ✓Break a problem into steps.
  • ✓Plan a project in parts.
Essential Question

How do you break a big problem into parts you can solve?

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Lesson Phases
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Vocabulary Terms
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Standards Aligned
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Interactive Task
Sort It · Interactive

Big Problem or Smaller Part?

Project this and sort each into a Big problem (too big to solve at once) or A smaller part (a doable piece).

🧩 Sort each — a big problem or a smaller part?Try it
🏔️ Big problem
🧩 A smaller part
Tap an item, then tap a box.
The Lesson · Use → Modify → Create (a coding progression with Unplugged practice)

50 minutes, five moves

Tap any phase to open the teacher moves and student actions.

1

Hook — Too Big to Chew

6 min

How would you even start building a whole game?

👩‍🏫 Teacher Moves

  • Show a huge goal.
  • Ask “where do we begin?”
  • Set the goal.

🎒 Student Actions

  • Think.
  • Guess.
  • Get ready.
2

Use — Decomposition

12 min

Students decompose.

👩‍🏫 Teacher Moves

  • Send students to Big Problem or Smaller Part?
  • Sort each item.
  • Note big goals split into pieces.

🎒 Student Actions

  • Sort.
  • Say.
  • Note it.
3

Modify — Split It Further

13 min

Students modify.

👩‍🏫 Teacher Moves

  • Take one part and split it again.
  • Order the smaller parts.
  • Spot the first step.

🎒 Student Actions

  • Split.
  • Order.
  • Spot.
4

Create — Plan a Project

13 min

Students create.

👩‍🏫 Teacher Moves

  • Pick a goal (make a comic).
  • List 3–4 smaller parts.
  • Mark which part is first.

🎒 Student Actions

  • Pick.
  • List.
  • Mark.
5

Reflect — Reflect

6 min

Students close.

👩‍🏫 Teacher Moves

  • Say what decomposition is.
  • Name one benefit.
  • Complete the exit ticket.

🎒 Student Actions

  • Say it.
  • Name one.
  • Complete the exit ticket.
Standards Alignment

Built to the standards you report on

Aligned to the CSTA K-12 Computer Science Standards and the ISTE Standards for Students.

CSTA
2-AP-13

Decompose problems into parts to design a program.

CSTA
2-AP-10

Use flowcharts/pseudocode to plan an algorithm.

CSTA
2-AP-17

Systematically test and refine a solution.

ISTE
5 Computational Thinker

Break problems into manageable parts.

Differentiation

One lesson, every learner

Multilingual Learners

ELL / EMERGING READERS
  • Use a jigsaw-puzzle analogy.
  • Label parts with pictures.
  • Pair talk before sorting.

Support & Access

IEP / 504
  • Sort big vs part only.
  • Use 3 items.
  • Use picture cards.

Stretch & Extend

GIFTED / EARLY FINISHERS
  • Decompose a part into sub-parts.
  • Diagram the whole breakdown.
  • Assign parts to a team.
Materials

What to gather

  • 📽️Screen / board
  • 🧩Problem/part cards
  • 💻Big Problem or Smaller Part?
  • 🗂️Project planner
  • 📓Notebooks
  • 🎫Exit-ticket slips
Vocabulary

Key terms — hover for a quick definition

decompositionbreaking a problem into smaller partsproblemthe big goal to solveparta smaller piece of the problemsubtaska small job within a taskplanthe order of parts to dofirst stepthe part you start withmanageablesmall enough to actually doorganizeto arrange the parts clearly
Evaluate

Exit Ticket

Preview the three formative checks. Tap “Sample answer” to see what mastery looks like — hide them before you print for students.

QUESTION 1
What is decomposition?
Breaking a big problem into smaller parts you can solve.
QUESTION 2
Is “build a whole game” a big problem or a small part?
A big problem.
QUESTION 3
Why decompose?
Smaller parts are easier to solve and share.

Reflect: decomposition.

Have students break one goal into 3 smaller parts. A printable decomposition planner is in the Computer Science library.

Study · Flashcards

Study the key terms

Tap a card to flip it, then rate whether you knew it. Built from this lesson’s vocabulary.

🃏 CS Decomposition (Grade 6)Flip
Card 1
Term
Tap to flip →
Meaning
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Nice work!

Practice · Quiz

Check your understanding

A quick self-check with instant feedback, drawn from this lesson’s key terms.

📝 CS Decomposition (Grade 6)Quiz
Score: 0
1 / 6
Question 1
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Nice work!

Practice · Worksheet

Printable worksheet

A print-and-go review sheet with a built-in answer key. Tap “Show answer key” to reveal answers, or print the clean version for students.

🖨️ CS Decomposition (Grade 6)Print
Name: ________________________
Date: ____________

Part A · Write the word that matches each meaning

Word bank: decomposition, first step, manageable, organize, part, plan, problem, subtask
  1. the order of parts to do
  2. a small job within a task
  3. breaking a problem into smaller parts
  4. the big goal to solve
  5. small enough to actually do
  6. the part you start with
  7. a smaller piece of the problem
  8. to arrange the parts clearly

Part B · Show what you learned

  1. What is decomposition?
  2. Is “build a whole game” a big problem or a small part?
  3. Why decompose?
Answer key — Part A: 1) plan · 2) subtask · 3) decomposition · 4) problem · 5) manageable · 6) first step · 7) part · 8) organize
Part B: 1) Breaking a big problem into smaller parts you can solve. 2) A big problem. 3) Smaller parts are easier to solve and share.