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OCR H446 1.4.3 Boolean logic and notation
Part 1 of 11 · H446 1.4.3 · Boolean algebra
OCR H446 1.4.3 opens with notation, and students who cannot turn a sentence into variables lose marks long before they reach a Karnaugh map. This first worksheet in the series builds that translation habit and separates AND, OR, NOT and XOR in the notation OCR uses.
Students will:
- represent two-state conditions as 0 and 1 using OCR operator symbols
- distinguish an inclusive OR from an exclusive XOR in a described situation
- define suitable variables for a written scenario before writing any expression
- write a Boolean expression that keeps the scope of a negation correct
- recall operator meanings without an answer bank in a closed-book check
Inside: 6 explanation cells, 3 multiple-choice questions, 2 fill-in-the-blanks cells and 1 written answer. 16 marks, about 35 to 45 minutes.
Series: H446 1.4.3 · Boolean algebra, part 1 of 11.
Shared by Coding PathwayVerified teacher
- 12 cells
- About 45 minutes
- CC BY-SA 4.0
- Shared 31 Aug 2026
- Updated 3 Sept 2026
Preview
The whole resource, exactly as a class sees it. Answers and marking are held back.
Boolean logic and notation
Computers often make decisions from conditions that are either true or false. Boolean algebra gives us a precise way to represent and combine those two-state conditions.
By the end, you will be able to
- represent false and true as 0 and 1;
- distinguish AND, OR, NOT and XOR;
- read OCR Boolean notation;
- define a short scenario as a Boolean expression.
No prior Boolean algebra is assumed.
Worked model: four operators, four different questions
- NOT reverses one input: ¬A.
- AND is true only when both inputs are true: A ∧ B.
- OR is true when at least one input is true, including when both are true: A ∨ B.
- XOR is true when exactly one input is true: A ⊕ B.
OCR uses ∧, ∨ and ¬ in questions, while accepting alternatives such as AND, OR and NOT. We will practise both forms but use OCR notation in final answers.
A door opens when card A or card B is valid, including when both cards are valid. Which operator models this?
- AOR
- BAND
- CXOR
- DNOT
| A | B | A ⊕ B |
|---|---|---|
| 0 | 0 | output for row 1 |
| 0 | 1 | output for row 2 |
| 1 | 0 | output for row 3 |
| 1 | 1 | output for row 4 |
For A=1 and B=1, which pair of outputs is correct for A OR B and A XOR B, in that order?
- A0, 0
- B1, 0
- C0, 1
- D1, 1
Worked model: turn words into variables
A studio light turns on when the room is occupied and test mode is not active.
Let O mean occupied, T mean test mode and L mean light. The expression is:
L = O ∧ ¬T
Translate each phrase once: ‘and’ gives ∧; ‘not active’ gives ¬T. Brackets become important when a NOT applies to a whole group rather than one variable.
A warning appears when the battery is low or the device is overheating, but only when maintenance mode is not active. Define suitable variables and write a Boolean expression for the warning.
State each variable meaning before writing the expression.
Students type their answer here.
Which expression means ‘NOT (A OR B)’?
- A¬A ∨ B
- B¬A ∨ ¬B
- C¬(A ∨ B)
- D(¬A) ∧ B
Examination lens
OCR questions may ask you to define a problem using Boolean logic. Marks come from translating every condition and its scope, not from naming gates without showing how they connect. Check whether ‘either’ means inclusive OR or exactly-one XOR from the scenario.
Closed-book checkpoint
Complete the statements from memory. There is no answer bank and checking is held for teacher review.
Review your responses
Check every response against its command word and the supplied constraints. Strengthen unsupported answers with accurate method, mechanism, state or contextual consequence before submitting.