10.1

Boolean logic

Cambridge IGCSE Computer Science (0478)  · Unit 10: Boolean logic  · 10 flashcards

Boolean logic is topic 10.1 in the Cambridge IGCSE Computer Science (0478) syllabus , positioned in Unit 10 — Boolean logic .  In one line: Boolean refers to a data type that has one of two possible values: true or false. It is fundamental to logic and decision-making within computer systems, forming the basis for Boolean algebra and logic gates.

This topic is examined in Paper 1 (computer systems theory) and Paper 2 (algorithms, programming and logic).

The deck below contains 10 flashcards — 4 definitions and 6 key concepts — covering the precise wording mark schemes reward.  Use the 4 definition cards to lock down command-word answers (define, state), then move on to the concept and application cards to handle explain, describe and compare questions.

Key definition

The term 'Boolean' in the context of computer science

Boolean refers to a data type that has one of two possible values: true or false. It is fundamental to logic and decision-making within computer systems, forming the basis for Boolean algebra and logic gates.

What the Cambridge 0478 syllabus says

Official 2026-2028 spec

These are the exact learning objectives Cambridge sets for this topic. Match the command word (Describe, Explain, State, etc.) in your answer to score full marks.

  1. Identify Identify and use the standard symbols for logic gates
  2. Define Define and understand the functions of the logic gates including NOT, AND, OR, NAND, NOR, XOR
  3. Use Use logic gates to create given logic circuits from a problem statement, logic expression or truth table
  4. Complete Complete a truth table from a problem statement, logic expression or logic circuit
  5. Write Write a logic expression from a problem statement, logic circuit or truth table
Definition Flip

Define the term 'Boolean' in the context of computer science.

Answer Flip

Boolean refers to a data type that has one of two possible values: true or false. It is fundamental to logic and decision-making within computer systems, forming the basis for Boolean algebra and logic gates.

Key Concept Flip

Explain the function of the 'AND' logical operator. Provide a truth table example.

Answer Flip

The 'AND' operator returns true only if both input conditions are true. Example truth table: True AND True = True, True AND False = False, False AND True = False, False AND False = False.

Key Concept Flip

Explain the function of the 'OR' logical operator. Provide a truth table example.

Answer Flip

The 'OR' operator returns true if at least one of the input conditions is true. Example truth table: True OR True = True, True OR False = True, False OR True = True, False OR False = False.

Key Concept Flip

Describe the effect of the 'NOT' logical operator. Provide a truth table example.

Answer Flip

The 'NOT' operator inverts the input condition. If the input is true, NOT returns false, and if the input is false, NOT returns true.

Example: NOT True = False, NOT False = True.
Key Concept Flip

What is a 'NAND' gate, and how does its output relate to an 'AND' gate?

Answer Flip

A 'NAND' gate is the opposite of an 'AND' gate; its output is only false if all inputs are true. It's essentially an AND gate followed by a NOT gate. NAND is shorthand for NOT AND.

Key Concept Flip

Explain the functionality of a 'NOR' gate and give an example with two inputs.

Answer Flip

A 'NOR' gate outputs true only if both inputs are false. It's the opposite of an OR gate.

Example: if input A is True and input B is False, the output of the NOR gate is False.
Key Concept Flip

Describe the behaviour of an 'XOR' gate. Create a truth table for it.

Answer Flip

An 'XOR' (exclusive OR) gate outputs true only when the inputs are different. Truth table: True XOR True = False, True XOR False = True, False XOR True = True, False XOR False = False.

Definition Flip

What is a truth table used for in Boolean logic?

Answer Flip

A truth table systematically lists all possible combinations of input values and their corresponding output values for a logical expression or gate. It helps in analyzing and understanding the behavior of logic circuits.

Definition Flip

What does it mean to 'simplify' a logic expression, and why is it useful?

Answer Flip

Simplifying a logic expression means rewriting it in a simpler, equivalent form. This is useful because it reduces the number of gates needed in a circuit, leading to lower cost, less power consumption, and faster performance.

Definition Flip

State De Morgan's Laws, and explain how they can be used to simplify Boolean expressions.

Answer Flip

De Morgan's Laws are: 1) NOT (A AND B) = (NOT A) OR (NOT B) and 2) NOT (A OR B) = (NOT A) AND (NOT B). They allow you to transform expressions with negations and help simplify complex logic.

Review the material

Read revision notes with definitions, equations, and exam tips.

Read Notes

Test yourself

Practice with MCQ questions to check your understanding.

Take Computer Science Quiz
9.2 SQL

Key Questions: Boolean logic

Define the term 'Boolean' in the context of computer science.

Boolean refers to a data type that has one of two possible values: true or false. It is fundamental to logic and decision-making within computer systems, forming the basis for Boolean algebra and logic gates.

What is a truth table used for in Boolean logic?

A truth table systematically lists all possible combinations of input values and their corresponding output values for a logical expression or gate. It helps in analyzing and understanding the behavior of logic circuits.

What does it mean to 'simplify' a logic expression, and why is it useful?

Simplifying a logic expression means rewriting it in a simpler, equivalent form. This is useful because it reduces the number of gates needed in a circuit, leading to lower cost, less power consumption, and faster performance.

State De Morgan's Laws, and explain how they can be used to simplify Boolean expressions.

De Morgan's Laws are: 1) NOT (A AND B) = (NOT A) OR (NOT B) and 2) NOT (A OR B) = (NOT A) AND (NOT B). They allow you to transform expressions with negations and help simplify complex logic.

Cambridge syllabus keywords to use in your answers

These are the official Cambridge 0478 terms tagged to this section. Mark schemes credit responses that use the exact term — weave them into your answers verbatim rather than paraphrasing.

Boolean AND OR NOT NAND NOR XOR truth table logic expression simplify De Morgan

Key terms covered in this Boolean logic deck

Every term below is defined in the flashcards above. Use the list as a quick recall test before your exam — if you can't define one of these in your own words, flip back to that card.

The term 'Boolean' in the context of computer science
Truth table used for in Boolean logic
What does it mean to 'simplify' a logic expression, and why is it useful
De Morgan's Laws, and explain how they can be used to simplify Boolean expressions

How to study this Boolean logic deck

Start in Study Mode, attempt each card before flipping, then rate Hard, Okay or Easy. Cards you rate Hard come back within a day; cards you rate Easy push out to weeks. Your progress is saved in your browser, so come back daily for 5–10 minute reviews until every card reads Mastered.