GCSE · Formulae & rearranging

Number machines and function machinesExam-style questions

A number machine is a list of instructions carried out in order. How to run one forwards, how to run it backwards by undoing the last box first, why the order of the boxes matters, how to write a machine as an expression with the brackets in the right place, how to find the number a machine leaves unchanged or a box that is missing, and how to join two machines, undo one in algebra and solve with them.

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11 questions · GCSE (Higher) level · mark scheme and worked solution on each · no sign-up to try

DifficultyAllLevel 2Level 3Level 4
  1. 1
    This is a function machine.

    Input→− 3→×5→Output\text{Input} \to \boxed{-\,3} \to \boxed{\times 5} \to \text{Output}

    Use xx for the input and yy for the output.

    Write yy in terms of xx.

    (2 marks)
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