GCSE · Rounding & bounds

Upper and lower boundsExam-style questions

Why a rounded value hides half a unit of uncertainty each way, why the upper bound is a strict "less than", how truncation differs, and how to pick the right bounds when calculating — the ÷ and − traps included.

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

DifficultyAllLevel 1Level 2Level 3Level 4Level 5
  1. 1
    A rectangle measures 8.3 cm by 6.4 cm, each correct to 1 decimal place.8.3 cm6.4 cmDiagram NOT accurately drawn

    Work out the upper bound of the area of the rectangle.
    Level 4 · 3 marksTry it
  2. 2
    A rectangle measures 1212 cm by 99 cm, each correct to the nearest centimetre.

    Work out the upper bound of the perimeter.
    Level 4 · 2 marksTry it
  3. 3
    A rectangle measures 8.38.3 cm by 6.46.4 cm, each correct to 11 decimal place.

    Work out the lower bound of the area of the rectangle.
    Level 4 · 2 marksTry it
  4. 4
    A car travels 120120 m, correct to the nearest 1010 m, in 15.615.6 seconds, correct to 1 decimal place.

    (a) Work out the upper bound for the average speed of the car. Give your answer correct to 3 significant figures. (3 marks)

    (b) Work out the lower bound for the average speed of the car. Give your answer correct to 3 significant figures. (1 mark)
    Level 4 · 4 marksTry it
  5. 5
    The radius of a circle is 6.46.4 cm, correct to 1 decimal place.

    (a) Work out the upper bound for the circumference of the circle. [2]

    (b) Work out the lower bound for the circumference. [1]

    (c) Use your answers to write down the circumference to a suitable degree of accuracy. Explain your choice. [1]
    Level 4 · 4 marksTry it

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