Computational thinking with Boolean logic
Computational thinking breaks a messy real-world question into small true/false decisions a machine can follow exactly.
Part of your national curriculum
- Computer systems and networks: Understand simple Boolean logic (for example AND, OR and NOT) and some of its uses in circuits and programming, and its use in computational thinking
Lesson overview
What you'll learn in this lesson
Understand simple Boolean logic (for example AND, OR and NOT) and some of its uses in circuits and programming, and its use in computational thinking
Key learning points
- • Decomposing a problem
- • Truth tables help you check your logic
- • Where this shows up
This lesson at a glance
- 25 minutes
- 14 parts to scroll through
- 3 quick checks
- Marked quiz at the end
- Gentle pace: short sittings with pauses
Words to know
Scroll down — the lesson carries on below
Watch & discover
Part 1 of 14
Watch first
Computational thinking with Boolean logic
An English teaching video on this topic from Spanning Tree. Watch it, then scroll down for the lesson.
In a nutshell
Understand simple Boolean logic (for example AND, OR and NOT) and some of its uses in circuits and programming, and its use in computational thinking
Learning cycle
Part 2 of 14
Learning cycle 1 of 2
Part 1 · Decomposing a problem
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 3 of 14
Learn
Decomposing a problem
To decide 'can this player level up?', break it into smaller checks: hasEnoughXP AND hasCompletedQuest AND NOT isBanned. Each check is a simple Boolean expression, and combining them with logic gives one reliable overall answer.
Explore the idea
Part 4 of 14
Learn
Truth tables help you check your logic
For A AND (B OR C), list every combination of true/false for A, B and C and work out the result row by row. Writing this out catches mistakes before you ever run the program, because you can compare it to what you intended.
Quick check
Part 5 of 14
Quick check
Why break a big decision into smaller Boolean checks?
Reset break
Part 6 of 14
Pause
That's sitting 1 of 2 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Quick check
Part 7 of 14
Quick check
A truth table for A AND B has how many rows for two inputs?
Learning cycle
Part 8 of 14
Learning cycle 2 of 2
Part 2 · Where this shows up
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 9 of 14
Learn
Where this shows up
Search engines use AND/OR between keywords, spreadsheet formulas use IF with AND/OR conditions, and traffic light controllers use logic such as NOT pedestrianCrossing AND carsWaiting. The same three gates keep reappearing.
Quick check
Part 10 of 14
Quick check
A search for 'cats AND dogs' returns pages that contain...
Challenge round
Part 11 of 14
Game · Sort it
Which of these are true?
Drag each card into the right column. Tap a card first if dragging is fiddly.
True
Not true
Challenge round
Part 12 of 14
Game · Fill the gaps
Finish the sentences
Choose the word that belongs in each gap.
Each check is a ____ Boolean expression, and combining them with logic gives one reliable overall answer.
Mastery quiz
Part 13 of 14
Marked quiz
End of lesson quiz: Computational thinking with Boolean logic
3 questions, marked with the reasoning shown. No timer.
1. Why break a big decision into smaller Boolean checks?
2. A truth table for A AND B has how many rows for two inputs?
3. A search for 'cats AND dogs' returns pages that contain...
Lesson round-up
Part 14 of 14
Lesson round-up
Ready when you are
Quiz score
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Points this lesson
0
Best run
0 in a row
Luna: 0 out of 3 on the practice checks. Only if you feel up to it — one more?
Ask LunaDo the work
Your written work for this lesson
This is the part you'd do in your book at school. Pick the pieces below, write here or on paper, and photograph anything you draw or work out.
How a supermarket checkout knows the price
When a barcode is scanned, the checkout does not store the price itself. It sends the barcode number to a database and reads back a record: product name, price, whether it needs an age check. The record is the single place the price lives, so changing one row changes every till in the shop at once.
Problems come from bad data, not bad scanners. If two products share a barcode, or a price update reaches the shop overnight but the till holds an old copy in its cache, customers are charged the wrong amount. Shops check this with test transactions: scan a known item, expect a known price, record what actually happened.
Good systems also log every scan. If a customer complains, the log shows exactly which record was used and when.
Written for Good Learning Co.
Reading questions
- Write in your own words what the checkout sends and what it receives back.
- Explain one way bad data could cause a wrong price, and how logging helps find it.
- Design a test table with four tests for a new checkout, with expected and actual results.
Reading and notes
ReadingRead the lesson text again and note the key terms and how each one is used, in your own words — as you would for revision.
Half a page of notes
Extended writing
WritingExplain a real system that uses this idea — how it works, where it can go wrong, and how you would make it safer or better.
250–350 words
Algorithm on paper
DiagramWrite your steps out as pseudocode or a flowchart before you type anything, then photograph it.
1 flowchart or 10 lines
Code write-up
WritingCopy your code in, then explain underneath what each part does and what you had to fix.
Code + 5 sentences
Test table
Working outMake a test table: what you tried, what you expected, what actually happened.
4–6 tests
Saved as you type.
Part 1 of 14 · Watch & discover
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Understand simple Boolean logic (for example AND, OR and NOT) and some of its uses in circuits and programming, and its use in computational thinking