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GCSE Maths / Edexcel

Rounding to significant figures

Round numbers to a given number of significant figures by counting important digits from the first non-zero digit.

Number and Place ValueFoundation and HigherGrades 4 to 7Focused skill

Curriculum path: GCSE Maths > Edexcel > Number > Rounding to significant figures

Pearson Edexcel GCSE Maths number: round to significant figures and use appropriate accuracy.

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Revision notes

Theory, examples, and quick checks.

Keep the method short, then practise straight away. This note is written for GCSE Maths Edexcel students who need clear working and reliable method marks.

Theory

Significant figures are the important digits in a number.

Start counting at the first non-zero digit. Zeros before that first non-zero digit are not significant.

After you have counted the required number of significant figures, look at the next digit to decide whether to round up.

Zeros between non-zero digits are significant. Zeros at the end can also be significant if they show the required accuracy.

For large whole numbers, digits after the rounded place become zeros.

Do not count from the decimal point unless the question asks for decimal places.

Key ruleSignificant figures start at the first non-zero digit.

Worked examples

Whole number

Round 3487 to 2 significant figures.

  1. Start counting at 3: first significant figure is 3.
  2. Second significant figure is 4.
  3. The next digit is 8, so round 34 up to 35 and replace the rest with zeros.

Answer: 3500

Small decimal

Round 0.08362 to 2 significant figures.

  1. Ignore the zeros before 8.
  2. The first two significant figures are 8 and 3.
  3. The next digit is 6, so round 0.083 to 0.084.

Answer: 0.084

Zero inside the number

Round 2.049 to 3 significant figures.

  1. Count from 2: the first three significant figures are 2, 0, and 4.
  2. The next digit is 9.
  3. 9 rounds the 4 up to 5.

Answer: 2.05

Common mistakes

  • Counting zeros before the first non-zero digit.
  • Treating significant figures like decimal places.
  • Forgetting to replace unused digits with zeros in large whole numbers.
  • Dropping a zero that is needed to show the rounded place.

Quick exercise

Try these before moving to the exam-style questions.

  1. Round 5832 to 2 significant figures.
  2. Round 0.004763 to 2 significant figures.
  3. Round 12.96 to 3 significant figures.
  4. Round 9042 to 1 significant figure.
  5. Round 0.0996 to 2 significant figures.
Exam-style questions

Practise the same skill at three levels.

These are original GCSE-style questions with mark schemes, common wrong answers, and AI marking guidance so feedback stays close to exam expectations.

Basic GCSE styleFoundation and HigherNon-calculator2 marks

Round 6472 to 2 significant figures.

significant figureswhole numbersfoundation number
Standard exam styleFoundation and HigherEither3 marks

Round 0.006738 to 2 significant figures.

small decimalssignificant figuresleading zeros
ChallengeHigherCalculator3 marks

A calculation gives 0.09964. Write the answer to 2 significant figures and explain why the zero at the end matters.

significant figuresaccuracytrailing zero