This topic summary covers Knowledge Organiser: Operators within Operators for GCSE Computer Science. Revise Operators in 3.2 Programming for GCSE Computer Science with 15 exam-style questions and 8 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 7 of 7 in this topic. Use this topic summary to connect the idea to the wider topic before moving on to questions and flashcards.
Knowledge Organiser: Operators
Key Terms
- Arithmetic operator: Performs a mathematical calculation (+, -, *, /, DIV, MOD)
- Comparison operator: Compares two values and returns true or false (==, !=, <, >, <=, >=)
- Logical operator: Combines boolean conditions (AND, OR, NOT)
- DIV: Integer division — divides and discards the remainder (e.g. 17 DIV 5 = 3)
- MOD: Modulus — returns only the remainder (e.g. 17 MOD 5 = 2)
Must-Know Facts
- / gives a real result; DIV gives an integer result (no remainder)
- MOD is used to check if a number is even:
number MOD 2 == 0 - Use == for comparison; = is for assignment
- AND: both conditions must be true; OR: at least one must be true; NOT: inverts the value
- 5 DIV 2 = 2 and 5 MOD 2 = 1 (together they give the full division result)
Key Concepts
- Check even/odd:
if number MOD 2 == 0 then(even) - Get last digit of a number:
number MOD 10 - Cycle through 0–9:
counter MOD 10 - Combine conditions:
if age >= 18 AND hasID == true then
Common Mistakes
- Confusing DIV and MOD: DIV gives the whole number part of a division (quotient); MOD gives the remainder — 17 DIV 5 = 3, 17 MOD 5 = 2
- Using = instead of == in conditions: = is assignment (gives a value); == is comparison (tests if equal) — using the wrong one is one of the most frequent pseudocode errors
- Confusing / and DIV: / (division) can give a real/decimal result; DIV always gives an integer result by discarding the remainder
- Mixing up AND and OR: AND requires BOTH conditions to be true; OR requires at least ONE — confusing them produces logic that accepts or rejects the wrong values
- Forgetting NOT inverts a boolean:
NOT truegives false and vice versa — useful for toggling flags or reversing conditions
Practice questions for Operators
Which symbol is used as the equality comparison operator in OCR pseudocode?
Describe how each of the three Boolean operators AND, OR, and NOT work. Include when each returns TRUE.
Quick recall flashcards
What does DIV do?
Integer division (discards remainder)
What does MOD do?
Returns the remainder after division