Community resourceWorksheet

J277 2.4.1 Boolean operators and truth tables

Part 1 of 4 · J277 2.4 · Boolean logic

The first Boolean logic worksheet for OCR J277 2.4.1, covering the three required operators and the truth tables that describe them.

Students will:

  • state what a Boolean value is and where a computer uses one
  • describe what AND, OR and NOT each do to their inputs
  • recognise the symbol for each of the three required gates
  • complete a truth table for a single operator
  • apply the operators to a stated real condition

Inside: 4 explanation cells, 3 multiple-choice questions, 1 fill-in-the-blanks cell and 2 written answers. 11 marks, about 45 minutes.

Series: J277 2.4 · Boolean logic, part 1 of 4.

Shared by Coding PathwayVerified teacher

  • 10 cells
  • About 45 minutes
  • CC BY-SA 4.0
  • Shared 17 Aug 2026
  • Updated 9 Sept 2026

Preview

The whole resource, exactly as a class sees it. Answers and marking are held back.

Boolean logic: AND, OR and NOT

A Boolean value has only two possible states: 1 or 0, which can also be written as True or False. Computer systems use Boolean logic whenever a decision depends on conditions.

For example, a rehearsal room may unlock only when a valid pass is detected AND the room is available. Each condition is either true or false, and a logical operator combines or changes those values.

OCR requires three operators:

  • AND, also called conjunction;
  • OR, also called disjunction;
  • NOT, also called negation.

Only AND, OR and NOT are required for OCR J277. The small circle on the end of a NOT gate matters: without it, the triangle does not represent NOT.

The three required gates

AND, OR and NOT logic gate symbols and their rules The AND gate has two inputs and outputs one only when both inputs are one. The OR gate has two inputs and outputs one when at least one input is one. The NOT gate has one input and reverses it. The NOT symbol is a triangle with a small circle at its output. The three OCR J277 logic gates ANDORNOT Output is 1 only when both inputs are 1. Otherwise the output is 0. Output is 1 when at least one input is 1. This includes the case where both inputs are 1. NOT has one input and reverses it. 0 becomes 1, and 1 becomes 0.
Multiple choice1 mark

A safety light turns on only when the door is closed and the guard is fitted. Which operator is required?

  • AOR
  • BNOT
  • CAND
  • DIteration
Multiple choice1 mark

A notification is sent when either the temperature is too high or the smoke sensor is active. Which operator is required?

  • AAND
  • BNOT
  • CSelection
  • DOR
Multiple choice1 mark

A signal called door_open is 1. What is the output of NOT door_open?

  • A0
  • B1
  • Cdoor_open
  • DIt cannot be known

Truth tables

A truth table records the output produced for every possible combination of Boolean inputs. With two inputs there are four combinations: 00, 01, 10 and 11.

ABA AND BA OR B
0000
0101
1001
1111
ANOT A
01
10

Notice the final OR row. In GCSE Boolean logic, OR means one or both inputs can be 1. It is not the everyday use of “either, but not both”.

Fill in the blanks4 marks
Complete the outputs. For inputs A = 0, B = 1, A AND B is label 1 and A OR B is label 2. For A = 1, B = 1, A AND B is label 3 and NOT A is label 4.
  • 0
  • 1
Written answer2 marks

State the purpose of a truth table.

Include both what it records and the range of input combinations it covers.

Students type their answer here.

Written answer2 marks

A music studio sounds an alarm when a door is open OR a window is open. Explain the output when both sensors are 1.

Name the operator, apply its rule, then state the output.

Students type their answer here.

Review

Close your notes and say one precise rule for each operator. Then sketch each gate on paper. Check that AND has a flat left edge and curved right edge, OR has a curved input side and pointed output, and NOT is a triangle with a small output circle.