GCSE (9–1) · GCSE Mathematics (Foundation with Higher stretch)
Chapter 4 Practice Paper
Estimation, rounding and bounds
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Original practice material written for the MOE GCSE Mathematics syllabus. It is not an official MOE or school examination paper. Chapter 4: rounding to d.p. and s.f., estimating with 1 s.f., error intervals for rounding and truncation, standard units with decimals, and upper and lower bounds of sums, products, quotients and speeds (Higher).
| For Examiner’s Use | |
|---|---|
| Section A | / 10 |
| Section B | / 20 |
| Total | / 30 |
Section A: Multiple-choice questions[10 marks]
Choose one answer for each question. Every correct answer scores one mark.
Round 5.271 to 1 decimal place.
Round 8264 to 2 significant figures.
Round 0.02068 to 2 significant figures.
Using 1 s.f. rounding, 41.2 × 8.7 is approximately
A number v is 12, rounded to 2 significant figures. Its error interval is
A number is truncated to 1 d.p. and shows 6.3. The error interval is
Write 90 minutes in hours as a decimal.
The lower bound of m = 3.6 to 1 d.p. is
With a = 5.2 and b = 1.4 (both to 1 d.p.), the upper bound of a × b is
A runner covers 400 m (nearest metre) in 50 s (nearest second). The maximum speed is
Section B: Structured questions[20 marks]
Show all your working. Marks are given for method as well as for the final answer.
Rounding in context.
A pencil is 17.86 cm long. Round this to 1 decimal place and to 2 significant figures.
A town’s population is 128 500. Round this to 3 significant figures.
Estimation.
By rounding each number to 1 significant figure, estimate the value of (58.3 × 6.9) ÷ 21.4.
Is the exact answer larger or smaller than your estimate? Give a reason.
Intervals of possible values.
A ladder is 4.2 m long to 1 d.p. Write an error interval for its length, l.
A different measurement, 2.8 m, was truncated to 1 d.p. Write an error interval for it.
Combined uncertainty. (Higher)
j = 6.1 and k = 3.4, both to 1 d.p. Find the bounds of j + k and j × k.
Work out the upper and lower bounds of the quotient j ÷ k, giving your answers to 3 significant figures.
The weight limit decision. (Higher)
A lift’s safe load is 400 kg. Six boxes each weigh 68 kg to 2 s.f. Can the lift be certain the boxes together are under the limit? Show your bounds.
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