Decomposing a problem into a hierarchy chart

Name:

Date:

Class:

Quick Questions

Shade in the A or B circle for each question.

1. Where does the main problem go in a hierarchy chart?

A In a box at the bottom

B In a single box at the top

2. Which is a sub-problem of the main problem 'Build a quiz app'?

A Show each question on the screen

B Build a quiz app

3. How is a hierarchy chart built?

A Split the problem into sub-problems, level by level

B Write every small task in one long row with no levels

4. When should you stop splitting a box into smaller boxes?

A When the task is small enough to solve on its own

B When the chart has exactly three levels

5. Which box is still too big to be a bottom-level task in a hierarchy chart for 'Make a school canteen ordering app'?

A Add up the price of the items in the cart

B Handle the whole ordering process

Match the Pairs

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

Left column		Right column
1Top box: Run a school canteen app		AThe sub-problem 'Write the code for everything' is still too big and is not a small task. It should be split into smaller sub-problems like Ask questions, Check answers and Show score.
2Run a school canteen app -> Take orders, Handle payments, Show menu		BSub-problems placed as boxes below the main problem, each one a smaller part of it
3Keep splitting a sub-problem until each box is a small task that can be solved on its own		CThe top box lists several tasks instead of one main problem. 'Make a quiz game' should be alone at the top, with the other tasks as sub-problem boxes below it.
4A small sub-problem box on the chart can later become a function in the program		DHandle payments -> Enter card details, Check funds, Print receipt
5Top box: Make a quiz game, Show score, Ask questions, Save high scores		EThe top-level problem box that states the one main problem to be decomposed
6Make a quiz game -> Write the code for everything		FBox: Check funds -> def check_funds(balance, price):

Definitions

hierarchy chart

Fill in the Blanks

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

Level _: Make a quiz app Level 2: Ask questions Level 2: Show score

Level 1: Make a quiz app Level 2: Ask questions Level _: Pick one question

____________: Make a quiz app Sub-problem: Ask questions Sub-problem: Show score

Box: Show score ________ showScore() PRINT score

IF task is too big THEN split it again ____ stop and solve it

Spot the Error

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

Question 1

A Main: Organise a school disco

B Sub: Organise a school disco

C Sub: Sell tickets

D Sub: Set up the hall

Question 2

A Main: Build a quiz app

B Sub: Make the questions

C Sub: Make the questions

D Sub: Show the score

Question 3

A Main: Make a weather app

B Sub: Get weather data

C Task: Build the whole app

D Sub: Display the forecast

Question 4

A Main: Run a canteen app

B Sub: Order -> order()

C Sub: Pay -> pay()

D Sub: Pickup -> pay()

Question 5

A Main: Create a school website

B Sub: Design the pages

C Sub: Write the content

D Sub: Bake a chocolate cake

Answer Key

Decomposing a problem into a hierarchy chart

Section A: Quick Questions

B — In a single box at the top

A — Show each question on the screen

A — Split the problem into sub-problems, level by level

A — When the task is small enough to solve on its own

B — Handle the whole ordering process

Section B: Match the Pairs

Top box: Run a school canteen app → The top-level problem box that states the one main problem to be decomposed

Run a school canteen app -> Take orders, Handle payments, Show menu → Sub-problems placed as boxes below the main problem, each one a smaller part of it

Keep splitting a sub-problem until each box is a small task that can be solved on its own → Handle payments -> Enter card details, Check funds, Print receipt

A small sub-problem box on the chart can later become a function in the program → Box: Check funds -> def check_funds(balance, price):

Top box: Make a quiz game, Show score, Ask questions, Save high scores → The top box lists several tasks instead of one main problem. 'Make a quiz game' should be alone at the top, with the other tasks as sub-problem boxes below it.

Make a quiz game -> Write the code for everything → The sub-problem 'Write the code for everything' is still too big and is not a small task. It should be split into smaller sub-problems like Ask questions, Check answers and Show score.

Section C: Definitions

hierarchy chart — A diagram that splits one main problem into smaller sub-problems in boxes, level by level, until each box is a small task that can be solved on its own.

Section D: Fill in the Blanks

Level 1: Make a quiz app
Level 2: Ask questions
Level 2: Show score

Level 1: Make a quiz app
Level 2: Ask questions
Level 3: Pick one question

Main problem: Make a quiz app
Sub-problem: Ask questions
Sub-problem: Show score

Box: Show score
FUNCTION showScore()
  PRINT score

IF task is too big THEN split it again
ELSE stop and solve it

Section E: Spot the Error

B — A sub-problem must be a smaller part of the main problem. This box just repeats the main problem, so it does not split anything. It should be a part such as 'Choose the music'.

C — Each sub-problem box must be a different part of the main problem. This box repeats 'Make the questions' from line 2, so the marking part is missing. It should be 'Sub: Mark the answers'.

C — A Task box is where we stop splitting, so it must be small enough to solve on its own. 'Build the whole app' is the original big problem. It should be a small task such as 'Read the city name'.

D — Each sub-problem later becomes its own function, so it needs its own matching name. pay() is already used by the 'Pay' box. The Pickup box should use pickup().

D — Every sub-problem must help solve the main problem. Baking a cake has nothing to do with creating a website. It should be a related part such as 'Test the links'.