Decomposition diagrams

Name:

Date:

Class:

Quick Questions

Shade in the A or B circle for each question.

1. Where does the whole problem go in a decomposition diagram?

A In the box at the top

B In a box at the bottom

2. Which box label is better for a school canteen app diagram?

A Show the menu

B Menu

3. What do the boxes on the level under the top box show?

A The final answer to the whole problem

B The smaller sub-problems that make up the whole problem

4. What does each new level down in the diagram give you?

A More detail about the problem

B A completely different problem

5. A box says 'Check the password is correct'. This is simple enough to do in one step. What should you do?

A Keep splitting it into tiny steps forever

B Stop splitting this box

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
1Plan a school disco		AThe label is just a noun, not an action phrase. It should say what to do, such as Choose the music.
2Choose music \| Set up speakers		BTwo sub-problem boxes on the level below the top box
3Label a box with an action phrase that starts with a verb		CBook the hall
4Level 2 adds more detail by splitting one box into smaller parts		DMake a poster -> Draw art \| Add date and time
5Box label: Music		EThe splitting did not stop when the part was simple. Press play is already easy enough to do, so it needs no more boxes.
6Keep splitting: Press play -> Move finger -> Bend knuckle		FThe whole problem, written in the single box at the top of the diagram

Definitions

decomposition diagram

Fill in the Blanks

Complete each line of code by filling in the missing parts.

Level _: Make a quiz app Level 2: Write questions | Show score

Box label = ____ + noun, e.g. Book hall

Stop splitting when a part is ______

Level 2: Plan food Level _: Buy drinks | Buy snacks

Sub-problems go _____ the whole problem

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A L0: Make a quiz game

B L1: Questions

C L1: Check the answers

D L1: Show the score

Question 2

A L0: Buy water bottles

B L1: Choose the events

C L1: Book the oval

D L1: Tell the students

Question 3

A L0: Build a school website

B L0: Design the layout

C L1: Write the page text

D L1: Test the links

Question 4

A L0: Make a class poster

B L1: Collect the facts

C L1: Draw the picture

D L1: Pick up the red pen

Question 5

A L0: Create a pet care app

B L1: Record feeding times

C L1: Bake a chocolate cake

D L1: Store pet photos

Answer Key

Decomposition diagrams

Section A: Quick Questions

A — In the box at the top

A — Show the menu

B — The smaller sub-problems that make up the whole problem

A — More detail about the problem

B — Stop splitting this box

Section B: Match the Pairs

Plan a school disco → The whole problem, written in the single box at the top of the diagram

Choose music | Set up speakers → Two sub-problem boxes on the level below the top box

Label a box with an action phrase that starts with a verb → Book the hall

Level 2 adds more detail by splitting one box into smaller parts → Make a poster -> Draw art | Add date and time

Box label: Music → The label is just a noun, not an action phrase. It should say what to do, such as Choose the music.

Keep splitting: Press play -> Move finger -> Bend knuckle → The splitting did not stop when the part was simple. Press play is already easy enough to do, so it needs no more boxes.

Section C: Definitions

decomposition diagram — A tree with the whole problem at the top and boxes below for its smaller sub-problems. Each level adds detail, and you stop splitting when a part is simple.

Section D: Fill in the Blanks

Level 1: Make a quiz app
Level 2: Write questions | Show score

Box label = verb + noun, e.g. Book hall

Stop splitting when a part is simple

Level 2: Plan food
Level 3: Buy drinks | Buy snacks

Sub-problems go below the whole problem

Section E: Spot the Error

B — Boxes in a decomposition diagram should be labelled with action phrases. 'Questions' is just a noun. It should say what to do, like 'Write the questions'.

A — The top of the tree must be the whole problem. 'Buy water bottles' is only one small part. It should be 'Plan a sports day'.

B — Only the whole problem is at level 0. A sub-problem directly below it should be level 1, so this line should start with L1.

D — Boxes on the same level should have a similar level of detail. 'Pick up the red pen' is a tiny step. It should be a level 1 part like 'Write the title'.

C — Every sub-problem must be a part of solving the whole problem. Baking a cake has nothing to do with a pet care app. It should be something like 'Show the vet details'.