DfE statement N15 · Number
Rounding, significant figures and error intervals
Rounding, significant figures and error intervals is content statement N15 of the DfE GCSE mathematics subject content, in the number area. It is on both tiers, and it appears on both the calculator and the non-calculator papers. Below is what the specification actually requires, the 3 mistakes that cost marks on this topic most often, and practice questions written to the statement — original questions, not past papers.
What the specification says
The DfE subject content for GCSE mathematics states, verbatim: "Round numbers and measures to an appropriate degree of accuracy (e.g. to a specified number of decimal places or significant figures); use inequality notation to specify simple error intervals due to truncation or rounding." (statement N15). Every awarding organisation — Pearson Edexcel, AQA and OCR — must cover it, so the wording is the same whichever specification your school follows.
Tier
Both tiers. This statement is Foundation content, which means Higher students are examined on it too — Higher is Foundation plus more, never instead of it.
Calculator
This turns up on both the non-calculator and the calculator papers, so practise it both ways — the written method for Paper 1 and the efficient calculator route for Papers 2 and 3.
Common mistakes
- Counting leading zeros as significant: 0.0450 to 2 significant figures is 0.045, because the first significant figure is the 4.
- Rounding in stages: taking 2.449 to 2.45 and then to 2.5 when 1 decimal place was asked for. Round once, from the original.
- Writing an error interval with the wrong inequality at each end. For a value rounded to the nearest 10, 45 ≤ x < 55 — the lower bound is included, the upper is not.
Sample questions (10 of 30)
Nearby statements
Questions people ask
Is rounding, significant figures and error intervals on Foundation or Higher?
Both. It is Foundation content, so it can be asked on either tier.
Can I use a calculator for rounding, significant figures and error intervals?
It depends on the paper. Paper 1 is non-calculator; Papers 2 and 3 allow one, and this topic is asked on both kinds.
What is the single most common mistake here?
Counting leading zeros as significant: 0.0450 to 2 significant figures is 0.045, because the first significant figure is the 4.
Are these past paper questions?
No. Every question is original, written to this DfE content statement and checked before publication. We do not host past papers or mark schemes.
Back to Number at Foundation or at Higher.