Lesson 4.3.3.1

4.3.3.1 Infix to Reverse Polish notation Quiz: AQA Computer Science, Unit 3

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 4.3.3.1, Infix to Reverse Polish notation: 20 multiple choice questions for the AQA Computer Science (7517), Unit 3: Fundamentals of algorithms, written with Revision Ninja.

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The 20 questions

  1. What is the Reverse Polish notation (postfix) form of the infix expression a + b?

    • a b +
    • a b + 1
    • + a b
    • a + b

  2. What main benefit does Reverse Polish notation provide over infix notation?

    • It evaluates expressions in parallel automatically
    • It removes the need for brackets within sub-expressions
    • It allows operators to appear only at the start of an expression
    • It makes expressions shorter by removing operands

  3. Which kind of system evaluates Reverse Polish expressions using a stack?

    • A queue-based task scheduler
    • A stack-based interpreter, such as one for PostScript or bytecode
    • A hash table lookup
    • A binary tree walker

  4. Which of these is an example of a stack-based system that uses RPN-style code?

    • HTML
    • PostScript
    • SQL
    • Spreadsheet formulas only

  5. When an operand is read during stack evaluation of an RPN expression, what happens to it?

    • It is compared with the top operator
    • It is pushed onto the stack
    • It is sent to the output as an operator
    • It is discarded

  6. Which RPN form represents the infix expression a * (b + c)?

    • * a + b c
    • a b * c +
    • a b + c *
    • a b c + *

  7. What is the value of the RPN expression 3 4 + 2 *?

    • 10
    • 24
    • 14
    • 11

  8. Which RPN expression is equivalent to the infix (a + b) * c - d?

    • a b + c d * -
    • - * + a b c d
    • a b c + * d -
    • a b + c * d -

  9. What is the value of the RPN expression 5 1 2 + 4 * + 3 -?

    • 17
    • 12
    • 14
    • 20

  10. What is the value of the infix expression 2 * 3 + 4 evaluated via its RPN form?

    • 9
    • 14
    • 10
    • 24

  11. Which RPN form represents the infix expression a - b - c?

    • a - b c -
    • a b - c -
    • a b c - -
    • - a - b c

  12. What is the value of the RPN expression 6 2 / 3 +?

    • 4.5
    • 1
    • 9
    • 6

  13. Which RPN form represents the infix expression a + b * c?

    • + a * b c
    • a b c * +
    • a b c + *
    • a b + c *

  14. Which RPN form represents the infix expression a - (b - c)?

    • a b c + -
    • a b c - -
    • a b - c -
    • - a b c

  15. An RPN expression a b c * + is evaluated with a = 1, b = 2 and c = 3. What is the result?

    • 10
    • 7
    • 9
    • 5

  16. Which RPN form represents the infix expression a + b * c - d / e?

    • a b c * + d e / -
    • - + a * b c / d e
    • a b + c * d e / -
    • a b c * d e / + -

  17. What is the value of the RPN expression 2 3 + 4 5 * -?

    • 15
    • -25
    • -15
    • 25

  18. Which RPN sequence would cause a stack underflow during evaluation?

    • 5 1 2 + 4 * + 3 -
    • 1 2 + +
    • 1 2 + 3
    • 3 4 * 2 -

  19. Why must a stack-based evaluator process an RPN expression from left to right?

    • Operators must appear before operands
    • The stack must hold brackets
    • Each operator's operands are the two items on top of the stack at that point
    • RPN is read from right to left

  20. What is the value of the RPN expression 4 2 * 3 -?

    • 5
    • 2
    • 11
    • 8

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