The four elements of computational thinking

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Quick Questions

Shade in the A or B circle for each question.

1. Which set lists the four elements of computational thinking?

A Decomposition, pattern recognition, abstraction, algorithms

B Decomposition, compiling, debugging, algorithms

2. A student breaks a school canteen app into smaller parts: menu, ordering, payment and pickup. Which element is this?

A Decomposition

B Abstraction

3. You notice that the login, signup and password reset screens all use the same email and password checks. Which element is this?

A Decomposition

B Pattern recognition

4. A transport map app shows only stations and lines, and leaves out buildings and street trees. Which element is this?

A Pattern recognition

B Abstraction

5. Which is an example of algorithmic thinking?

A Writing clear step-by-step instructions to sort students into teams

B Ignoring details that do not matter to the problem

Match the Pairs

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

Left column		Right column
1Decomposition		ADecomposition does the opposite. It splits a big problem into smaller sub-problems rather than combining them.
2Pattern recognition		BIgnore the bus colour; keep route, stop and time
3Abstraction hides unimportant detail and keeps only what matters to the problem		C1. Read mark 2. If mark >= 50 then PASS 3. Else FAIL
4Algorithmic thinking writes clear step-by-step instructions to solve the problem		DBreaking a large problem into smaller, more manageable sub-problems
5Decomposition = combining all the parts into one big problem		ESpotting similarities or repeated features so one solution can be reused
6Abstraction = adding as much detail as possible to the model		FAbstraction removes unnecessary detail. It keeps only the details that are relevant to the problem.

Definitions

computational thinking

Fill in the Blanks

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

_____________: break a problem into parts

___________________: spot what repeats

___________: ignore details you do not need

_________: ordered steps that solve it

Problem: canteen ordering app Split it, spot patterns, ignore extras, write steps = ______________________

Spot the Error

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

Question 1

A DECOMPOSE: merge disco plan

B part1: book venue

C part2: choose music

D part3: sell tickets

Question 2

A PATTERN: quiz apps

B Quiz A: question, 4 options

C Quiz B: no questions at all

D Shared: question + options

Question 3

A ABSTRACT: train map

B keep: stations, lines

C ignore: station names

D result: simple map

Question 4

A ALGORITHM: make toast

B 1. butter the toast

C 2. press lever

D 3. wait then remove

Question 5

A INPUT mark

B IF mark <= 50 THEN

C OUTPUT 'Pass'

D ELSE OUTPUT 'Fail'

E ENDIF

Answer Key

The four elements of computational thinking

Section A: Quick Questions

A — Decomposition, pattern recognition, abstraction, algorithms

A — Decomposition

B — Pattern recognition

B — Abstraction

A — Writing clear step-by-step instructions to sort students into teams

Section B: Match the Pairs

Decomposition → Breaking a large problem into smaller, more manageable sub-problems

Pattern recognition → Spotting similarities or repeated features so one solution can be reused

Abstraction hides unimportant detail and keeps only what matters to the problem → Ignore the bus colour; keep route, stop and time

Algorithmic thinking writes clear step-by-step instructions to solve the problem → 1. Read mark 2. If mark >= 50 then PASS 3. Else FAIL

Decomposition = combining all the parts into one big problem → Decomposition does the opposite. It splits a big problem into smaller sub-problems rather than combining them.

Abstraction = adding as much detail as possible to the model → Abstraction removes unnecessary detail. It keeps only the details that are relevant to the problem.

Section C: Definitions

computational thinking — Solving problems by using decomposition, pattern recognition, abstraction and algorithms so a computer or person can carry out the solution.

Section D: Fill in the Blanks

decomposition: break a problem into parts

pattern recognition: spot what repeats

abstraction: ignore details you do not need

algorithm: ordered steps that solve it

Problem: canteen ordering app
Split it, spot patterns, ignore extras,
write steps = computational thinking

Section E: Spot the Error

A — Decomposition breaks a big problem into smaller sub-problems. It does not merge them together. The line should say 'split disco plan'.

C — Pattern recognition finds what things have in common. Quiz B must also have a question and 4 options to match Quiz A and the shared line.

C — Abstraction removes detail that is not needed, so a train map would not ignore station names. Seat colour is the irrelevant detail to ignore.

B — An algorithm needs steps in the right order. You cannot butter toast that has not been made yet. Step 1 should be putting the bread in the toaster.

B — The algorithm's condition is reversed, so low marks would pass and high marks would fail. It should be mark >= 50.