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GCSE Mathematics · key term
A value close to an exact value, found using convenient approximations rather than an exact calculation.
Used by AQA, Edexcel and OCR
Specification N6, N14, S5 · Paper 1, Paper 2, Paper 3
A value close to the exact answer, found using suitable known values or approximations.
Revise: Powers and RootsFor Higher tier, you must be able to estimate roots of positive numbers that are not exact powers. Start with nearby known powers.
A value inferred from sample data and used as an approximate value for the population.
When estimating, write down known powers on either side of the target. The inequalities justify your estimate even if several rounded answers would be reasonable.
Show the approximations you use before calculating; an unsupported decimal is not clearly an estimate.
Choose nearby numbers that make the calculation easy, usually using one significant figure, but keep enough information to produce a useful estimate.
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Specification N14, S5 · Paper 1, Paper 2, Paper 3
A value close to an exact answer, found without carrying out the full calculation.
Revise: EstimationAn estimate gives an answer that is close enough for a particular purpose, often much more quickly. You can also estimate before calculating: it gives you an expectation against which to check your final answer, including one produced by a calculator.
An approximate value obtained from available information rather than an exact count or measurement.
Specification 2.02b, 3.01b, 4.01b · Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Foundation), Paper 4 (Higher), Paper 5 (Higher), Paper 6 (Higher)
A number used to give a sensible approximation against which an exact answer can be checked.
Revise: Decimal ArithmeticUse an estimate to test both the size and the position of the decimal point.
A value close enough to the exact value for the stated purpose, usually found by comparison or suitable rounding.
A calculation that gives a sensible value close to the exact answer, usually by replacing numbers with convenient approximations.